1) Problem #PRAE69E "PRAE69E - 146045 - For these 2 que..." |
A)
For these 2 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided guidelines, how do you feel the AP Readers would grade you response? |
Multiple Choice:
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C)
Now, using the following information please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Solution Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Write a reflection on what you learned from this assignment. For this AP question, what did you do right? What did you do wrong? |
Ungraded Open Response: |
2) Problem #PRAE7XK "PRAE7XK - 146701 - 2010 AP Statistic..." |
A)
2010 AP Statistics Open Response Question 3 For these three questions, answer them in your notebook as you would if you were taking the AP exam. This question has an open response component. Please type in "completed assignment in notebook" and hit submit. Only hit submit AFTER AND ONLY AFTER YOU ARE FINISHED. |
Ungraded Open Response: |
B)
Use the following answer and scoring guidelines to grade your open response to see how you would've done. Using the provided scoring guidelines, how do you feel AP readers would grade your response? |
Multiple Choice:
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C)
Use the following answer and scoring guidelines to grade your open response to see how you would've done. Solution: Scoring: Using the provided scoring guidelines, how do you feel the AP readers would grade your response? |
Multiple Choice:
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D)
Use the following answer and scoring guidelines to grade your open response to see how you would've done. Solution: Scoring: Using the provided scoring guidelines, how do you feel the AP readers would grade your response? |
Multiple Choice:
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E)
Write a reflection on what you learned from this assignment. For these three AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
3) Problem #PRAE6MV "PRAE6MV - 145439 - " |
A)
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Ungraded Open Response: |
B)
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Multiple Choice:
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C)
Solution |
Multiple Choice:
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D)
Solution |
Multiple Choice:
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E)
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Ungraded Open Response: |
4) Problem #PRAE7HU "PRAE7HU - 146306 - Answer the questi..." |
A)
Answer the question below. You may also want to write your answers in your notebook so that you can more easily check your answers. |
Algebraic Expression: |
B)
Mark what you think your answer would receive. |
Multiple Choice:
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C)
Mark what you think your answer would receive. |
Multiple Choice:
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D)
Mark what you think your answer would receive. |
Multiple Choice:
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E)
Mark what you think your answer would recieve. |
Multiple Choice:
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F)
Write a reflection on what you learned from doing this assignment. In
addition, what answers did you get correct? What mistakes did you make? |
Ungraded Open Response: |
5) Problem #PRAE69A "PRAE69A - 146041 - Answer in y..." |
A)
Answer in your notebook just as you would if you were taking the AP exam. This question has an open response component. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. |
Multiple Choice:
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D)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response.
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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E)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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F)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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G)
Write a reflection on what you have learned from this assistment. |
Ungraded Open Response: |
6) Problem #PRAEMKQ "PRAEMKQ - AP QUESTION - 2010 FORM B - QUESTION 1" |
A)
For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. SOLUTION Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. SOLUTION: Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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E)
Write a reflection on what you learned from this assignment. For these 3 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
7) Problem #PRAE6WT "PRAE6WT - 145716 - 2010 AP Statisti..." |
A)
2010 AP Statistics Form B (Question #2) In response to nutrition concerns raised last year about food served in school cafeterias, the Smallville School District entered into a one-year contract with the Healthy Alternative Meals (HAM) company. Under this contract, the company plans and prepares meals for 2,500 elementary, middle, and high school students, with a focus on good nutrition. The school administration would like to survey the students in the district to estimate the proportion of students who are satisfied with the food under this contract. Two sampling plans for selecting the students to be surveyed are under consideration by the administration. One plan is to take a simple random sample of students in the district and then survey those students. The other plan is to take a stratified random sample of students in the district and then survey those students.
(a) Describe a simple random sampling procedure that the administrators could use to select 200 students from the 2,500 students in the district. |
Ungraded Open Response: |
B)
Solution to Question 2a
The administrators could number an alphabetical list of students from 1 to 2,500. They could then use a random number generator from a calculator or computer to generate 200 unique random integers from 1 to 2,500. The students corresponding to those 200 numbers would be asked to participate in the survey. Scoring to 2a is scored as follows:
Essentially correct (E) if the response describes a sampling procedure for generating a simple random sample and the description of the sampling procedure includes sufficient detail for implementation. Partially correct (P) if random selection is used correctly for generating a simple random sample, but the description of the sampling procedure does not provide sufficient detail for implementation. Incorrect (I) if random selection is not used in a correct way for a simple random sample. Note: A response in which objects are placed into a hat or a box and then drawn out can only earn an “E” if the response explicitly states that the objects are mixed or that they are drawn out at random.
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Multiple Choice:
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C)
Refer to the main problem above (b) If a stratified random sampling procedure is used, give one example of an effective variable on which to stratify in this survey. Explain your reasoning. |
Ungraded Open Response: |
D)
Solution to Question 2b One possible stratification variable might be the school level of the student (elementary, middle, high school). The students’ perceptions of the importance of good nutrition in food served may differ depending on the students’ ages and therefore on school levels. For example, there may be a difference between what elementary students value in food served as opposed to middle school and high school students. Scoring Guidelines to 2b Essentially correct (E) if the response identifies a reasonable stratification variable and provides a reasonable justification in context (such as stating, “the groups (strata) might differ with respect to food preferences or nutritional awareness”). Partially correct (P) if the response identifies a reasonable stratification variable but provides a weak justification (such as stating only, “the groups (strata) differ”). Incorrect (I) if the response identifies an unreasonable stratification variable, or provides an unreasonable justification or no justification. |
Multiple Choice:
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E)
Refer to the main problem above (c) Describe one statistical advantage of using a stratified random sample over a simple random sample in the context of this study. |
Ungraded Open Response: |
F)
Essentially correct (E) if the response provides a reasonable statistical advantage of stratified random sampling that is not also true of random sampling, and that is clearly communicated and in context. Partially correct (P) if the response provides a reasonable statistical advantage that is either not well communicated or that is not in context. Incorrect (I) if the response includes only a vague potential statistical advantage, such as “data more accurate” or “stratified random sampling is better.” Note: Responses to part (c) such as “stratified random sampling allows for inferences to be drawn for the three grade levels separately about the feelings of students in those grade levels” should be considered incorrect unless also accompanied by a statistical advantage specific to stratified random sampling. |
Multiple Choice:
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8) Problem #PRAE63W "PRAE63W - 145874 - 2010B Question 3" |
A)
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Multiple Choice:
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B)
Do this problem out in your notebook. Did you do the problem? |
Multiple Choice:
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C)
Round to 3 decimal places. |
Algebraic Expression:
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D)
Check your work with the solutions below. Did you check your work? |
Multiple Choice:
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E)
Given the scoring guidelines, how would an AP grader grade your response to part a? |
Multiple Choice:
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F)
Given the scoring guidelines, how would an AP grader grade your response to part b? |
Multiple Choice:
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G)
Given the scoring guidelines, how would an AP grader grade your response to part c? |
Multiple Choice:
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9) Problem #PRAE72R "PRAE72R - 146799 - A husband and a w..." |
A)
A husband and a wife, Mike and Lori, share a digital music player that has a feature that randomly selects which song to play. A total of 2,384 songs were loaded on to the player, some by Mike and the rest by Lori. Suppose that when the player was in the random-selection mode, 13 of the first 50 songs selected were songs loaded by Lori. Construct and interpret a 90 percent confidence interval for the proportion of songs on the player that were loaded by Lori. |
Multiple Choice:
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B)
Mike and Lori are unsure about whether the player samples the songs with replacement or without replacement when the player is in random-selection mode. Explain why this distinction is not important for the construction of the interval in the previous problem. |
Ungraded Open Response: |
10) Problem #PRAE698 "PRAE698 - 146070 - Fo..." |
A)
For these 4 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. After you are finished, AND ONLY AFTER YOU ARE FINISHED, type "completed assignment in notebook" and hit submit. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Solution: Scoring Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Solution: Scoring: Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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E)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Solution: Scoring: Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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F)
Write a reflection on what you learned from this assignment. For these 3 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
11) Problem #PRAE7JF "PRAE7JF - 146325 - Answer part (a) ..." |
A)
Answer part (a) in notebook. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Answer part (b) in notebook. |
Multiple Choice:
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D)
Using the provided score guidelines, how do you feel the AP Readers would grade your response? Solution Scoring |
Multiple Choice:
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E)
Answer part (c) in notebook. |
Multiple Choice:
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F)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Solution Scoring |
Multiple Choice:
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G)
Answer parts (d) and (e) in notebook. |
Multiple Choice:
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H)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Solutions Scoring |
Multiple Choice:
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I)
Write a reflection on what you learned from this assistment. For these AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
12) Problem #PRAE7J3 "PRAE7J3 - 146344 - Answer part ..." |
A)
Answer part a in your notebook. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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C)
Answer part b in your notebook. |
Multiple Choice:
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D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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E)
Answer part c in your notebook. |
Multiple Choice:
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F)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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G)
Write a short reflection of what you learned. |
Ungraded Open Response: |
13) Problem #PRAE7BA "PRAE7BA - AP Open Response EC" |
A)
Before beginning a unit on frog anatomy, a seventh-grade biology teacher gives each of the 24 students in the class a pretest to assess their knowledge of frog anatomy. The teacher wants to compare the effectiveness of an instructional program in which students physically dissect frogs with the effectiveness of a different program in which students use computer software that only simulates the dissection of a frog. After completing one of the two programs, students will be given a posttest to assess their knowledge of frog anatomy. The teacher will then analyze the changes in the test scores (score on posttest minus score on pretest). A) Describe a method for assigning the 24 students to two groups of equal size that allows for a statistically valid comparison of the two instructional programs. B) Suppose the teacher decided to allow the students in the class to select which instructional program on frog anatomy (physical dissection or computer simulation) they prefer to take, and 11 students choose actual dissection and 13 students choose computer simulation. How might that self-selection process jeopardize a statistically valid comparison of the changes in the test scores (score on posttest minus score on pretest) for the two instructional programs? Provide a specific example to support your answer. |
Ungraded Open Response: |
B)
Solution: A) Completely randomized design Each student will be assigned a unique random number using a random number generator on a calculator, statistical software, or a random number table. The assigned numbers will be listed in ascending order. The students with the lowest 12 numbers in the ordered list will receive the instructional program that requires physically dissecting frogs. The students with the highest 12 numbers will receive the instructional program that uses computer software to simulate the dissection of a frog. B) By not randomizing and allowing the students to self-select, there is a potential for changes to occur in the differences between pretest and posttest scores for a particular group because of the characteristics of students who choose a particular instructional method, not because of the instructional method itself. For example, suppose frog-loving students already know a lot about frog anatomy; one would therefore expect these students to be less likely to show a large change between the pretest and posttest scores. Suppose the frog-loving students tend to select the computer simulation method (perhaps because they do not like the notion of dissecting the frogs they love). The possible low change between pretest and posttest scores for the computer simulation group might then be attributed to the students' already knowing a lot about frog anatomy beforehand, not to the instructional method itself. The frog dissection group might see a larger change in scores because the students entering this group are those with the lower pretest scores (less prior knowledge) and who are thus more likely to show greater improvement between pretest and posttest scores. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Write a reflection on what you have done and learned. |
Ungraded Open Response: |
14) Problem #PRAE7KA "PRAE7KA - 146351 - Answer part a i..." |
A)
Answer part a in your notebook. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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C)
Answer part b in your notebook. |
Multiple Choice:
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D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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E)
Write a short reflection of what you learned. |
Ungraded Open Response: |
15) Problem #PRAE7HP "PRAE7HP - 146301 - For these 2 ques..." |
A)
For these 2 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. After you are finished, AND ONLY AFTER YOU ARE FINISHED, type "completed assignment in notebook" and hit submit. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Solution: Scoring: Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Write a reflection on what you learned from this assignment. For these 3 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
16) Problem #PRAE7KE "PRAE7KE - 146355 - Answer part a i..." |
A)
Answer part a in your notebook. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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C)
Answer part b in your notebook. |
Multiple Choice:
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D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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E)
Answer part c in your notebook. |
Multiple Choice:
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F)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? Then provide E, P, or I as possible multiple choice answers. |
Multiple Choice:
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G)
Write a short reflection on what you have learned. |
Ungraded Open Response: |
17) Problem #PRAE7H6 "PRAE7H6 - 146316 - For these 2 ques..." |
A)
For these 2 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response, just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Write a reflection on what you learned from this assignment. For these 2 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
18) Problem #PRAEJCP "PRAEJCP - Probability - AP EXAM QUESTION - 2009B Q2" |
A)
Here is an actual AP exam question: Give answer as a percentage rounded to the nearest whole number. Do not include % sign. |
Algebraic Expression:
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Hints: |
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B)
Give answer as a percentage rounded to the nearest whole number. Do not include % sign. |
Algebraic Expression:
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Hints: |
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C)
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Algebraic Expression:
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Hints: |
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19) Problem #PRAE733 "PRAE733 - 146840 - 2009 AP® STA..." |
A)
2009 AP® STATISTICS FREE-RESPONSE QUESTIONS (Form B) STATISTICS SECTION II Part A Question: 3 Spend about 65 minutes on this part of the exam. Percent of Section II score—75 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy and completeness of your results and explanations. 3. A French study was conducted in the 1990s to compare the effectiveness of using an instrument called a cardiopump with the effectiveness of using traditional cardiopulmonary resuscitation (CPR) in saving lives of heart attack victims. Heart attack patients in participating cities were treated with either a cardiopump or CPR, depending on whether the individual’s heart attack occurred on an even-numbered or an odd-numbered day of the month. Before the start of the study, a coin was tossed to determine which treatment, a cardiopump or CPR, was given on the even-numbered days. The other treatment was given on the odd-numbered days. In total, 754 patients were treated with a cardiopump, and 37 survived at least one year; while 746 patients were treated with CPR, and 15 survived at least one year. (a) The conditions for inference are satisfied in the study. State the conditions and indicate how they are satisfied. (b) Perform a statistical test to determine whether the survival rate for patients treated with a cardiopump is significantly higher than the survival rate for patients treated with CPR. Answer questions a-b below, and/or in your notebook.
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Ungraded Open Response: |
B)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments". AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 3 Intent of Question The primary goals of this question were to assess students’ ability to (1) state and check appropriate conditions for inference in a study, (2) state the appropriate hypotheses for a statistical test, (3) identify and compute the appropriate test statistic, and (4) make a conclusion in the context of the problem. Solution Let A represent the cardiopump treatment, and let B represent the CPR treatment. Let = A p proportion of patients who will survive at least one year if treated with the cardiopump. Let = B p proportion of patients who will survive at least one year if treated with CPR. Part (a): Step 1: State the conditions for inference. The conditions required for a two-sample z test of equal proportions for an experiment are: 1. Random assignment of treatments to subjects 2. Sufficiently large sample sizes Step 2: Check the conditions. 1. If we assume that the relevant characteristics of people who have heart attacks on even- numbered and odd-numbered days are comparable, randomly assigning one treatment to be given on even-numbered days and the other to be given on odd-numbered days is a reasonable approximation to randomly assigning the two treatments to the available subjects. 2. The large sample condition is met because all of the following are at least 5 (or 10):
Scoring This problem is scored in four sections. Section 1 consists of part (a). Section 2 consists of part (b), step 1. Section 3 consists of part (b), steps 2 and 3. Section 4 consists of part (b), step 4. Section 1 is scored as essentially correct (E), partially correct (P), or incorrect (I). Sections 2, 3, and 4 are each scored as essentially correct (E) or incorrect (I). Section 1 [part (a)] is scored as follows: Essentially correct (E) if the student correctly states and addresses randomization with reasonable justification AND correctly checks that the numbers of successes and failures are at least 5 or 10. Partially correct (P) if the student correctly states and checks only one condition, OR if the student states both conditions correctly but checks neither of them. Incorrect (I) otherwise. Please grade your answer as an AP Reader would. |
Multiple Choice:
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C)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments". AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 3 Intent of Question The primary goals of this question were to assess students’ ability to (1) state and check appropriate conditions for inference in a study, (2) state the appropriate hypotheses for a statistical test, (3) identify and compute the appropriate test statistic, and (4) make a conclusion in the context of the problem. Solution Let A represent the cardiopump treatment, and let B represent the CPR treatment. Let = A p proportion of patients who will survive at least one year if treated with the cardiopump. Let = B p proportion of patients who will survive at least one year if treated with CPR. Part (b): Step 1: State a correct pair of hypotheses.
Step 2: Identify a correct test by name or by formula. Two-sample z test for proportions OR
Step 4: State a correct conclusion in the context of the problem, using the result of the statistical test. Because the p-value of 0.0011 is very small, that is, less than any reasonable significance level such as a=0.01, or a=0.05, we reject the null hypothesis. We have strong evidence to support the conclusion that the proportion of patients who survive when treated with the cardiopump is higher than the proportion of patients who survive when treated with CPR; that is, the survival rate is higher for patients treated with the cardiopump. (OR, If all of these patients had been assigned the cardiopump, we have strong evidence that the survival rate would be higher than if all of these patients had been assigned CPR.) Scoring This problem is scored in four sections. Section 1 consists of part (a). Section 2 consists of part (b), step 1. Section 3 consists of part (b), steps 2 and 3. Section 4 consists of part (b), step 4. Section 1 is scored as essentially correct (E), partially correct (P), or incorrect (I). Sections 2, 3, and 4 are each scored as essentially correct (E) or incorrect (I). Section 2 [part (b), step 1] is scored as follows: Essentially correct (E) if the student states a correct pair of hypotheses. Note: The hypotheses may be stated using words or using transparent variable notation such as CPR p and , CP p even if the parameters are not defined. Incorrect (I) otherwise. Note: Hypotheses that clearly address sample proportions are incorrect. It must be clear that the hypotheses are not about the sample proportions. Section 3 [part (b), steps 2 and 3] is scored as follows: Essentially correct (E) if the student identifies a correct test and includes correct mechanics. Note: The mechanics are considered correct if the student uses a pooled test procedure or an unpooled test procedure, as long as the correct value of z is calculated. Incorrect (I) otherwise. Note: If the student writes the formula for the unpooled version but gets the correct values for the test statistic and p-value for the pooled version, section 3 is scored as incorrect. Section 4 [part (b), step 4] is scored as follows: Essentially correct (E) if the student states a correct conclusion in the context of the problem. Note: A correct conclusion in context must explicitly state that the cardiopump survival rate is significantly higher than the CPR survival rate. Incorrect (I) otherwise. Notes: • If the p-value in section 3 is incorrect but the conclusion is consistent with the computed p-value, section 4 can be considered correct. • In section 4 if both an aand a p-value are given together, the linkage between the p-value and the conclusion is implied. If no ais given, the solution must be explicit about the linkage by giving a correct interpretation of the p-value or explaining how the conclusion follows from the p-value. • If, instead of a one-sided test, a student correctly performs a two-sided test (chi-square test for homogeneity of proportions or a two-sided z test for comparing two proportions), the final score drops automatically by 1 point. Please grade your answer as an AP Reader would. |
Multiple Choice:
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D)
Write a reflection on what you learned from doing this assignment. In addition, what answers did you get correct? What mistakes did you make? |
Ungraded Open Response: |
20) Problem #PRAE74U "PRAE74U - 146864 - 2009 AP® STA..." |
A)
2009 AP® STATISTICS FREE-RESPONSE QUESTIONS (Form B) STATISTICS SECTION II Part A Question 4 Spend about 0-65 minutes on this part of the exam. Percent of Section II score—75 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy and completeness of your results and explanations. 4. A manufacturer of toxic pesticide granules plans to use a dye to color the pesticide so that birds will avoid eating it. A series of experiments will be designed to find colors or patterns that three bird species (blackbirds, starlings, and geese) will avoid eating. Representative samples of birds will be captured to use in the experiments, and the response variable will be the amount of time a hungry bird will avoid eating food of a particular color or pattern. (a) Previous research has shown that male birds do not avoid solid colors. However, it is possible that males might avoid colors displayed in a pattern, such as stripes. In an effort to prevent males from eating the pesticide, the following two treatments are applied to the pesticide granules. Treatment 1: A red background with narrow blue stripes Treatment 2: A blue background with narrow red stripes To increase the power of detecting a difference in the two treatments in the analysis of the experiment, the researcher decided to block on the three species of birds (blackbirds, starlings, and geese). Assuming there are 100 birds of each of the three species, explain how you would assign birds to treatments in such a block design. (b) Other than blocking, what could the researcher do to increase the power of detecting a difference in the two treatments in the analysis of the experiment? Explain how your approach would increase the power. Answer questions a-b below, and/or in your notebook. |
Ungraded Open Response: |
B)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments".
AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 4 Intent of Question The primary goals of this question were to assess students’ ability to (1) describe assignment of experimental units to treatments in a block design and (2) provide ways to increase the power of an experiment. Solution Part (a): Form three blocks based on the species of bird (blackbirds, starlings, and geese) to accomplish the goal of blocking to create groups of homogeneous experimental units. Within each of the three blocks, carry out a completely randomized design by randomly assigning the birds within each block to one of the two treatments. Within block 1, each bird of a particular species (let’s say the blackbirds) will be tagged with a unique random number using a random number generator on a calculator, statistical software, or a random number table. The random numbers will be sorted from lowest to highest. The birds with the lowest 50 numbers in the ordered list will receive treatment 1 (red background with narrow blue stripes). The birds with the highest 50 numbers will receive treatment 2 (blue background with narrow red stripes). This method of randomization should be repeated in the other two b
Scoring Parts (a) and (b) are each scored as essentially correct (E), partially correct (P), or incorrect (I). Part (a) is scored as follows: Essentially correct (E) if the student describes a method for randomization that (1) randomly assigns the two treatments to the birds within each of the three blocks and (2) describes the method with sufficient detail so that a knowledgeable statistics user could replicate the method. Partially correct (P) if the student describes a method for randomization within blocks but does not provide sufficient detail so that a knowledgeable statistics user could replicate the method OR the method of randomization does not guarantee sufficient randomization. Incorrect (I) if there is no randomization or if the randomization is not done within blocks. Note: The sample sizes within the treatment groups are not required to be equal. Please grade your answer as an AP Reader would.
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Multiple Choice:
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C)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments".
AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 4 Intent of Question The primary goals of this question were to assess students’ ability to (1) describe assignment of experimental units to treatments in a block design and (2) provide ways to increase the power of an experiment. Solution Part (b): To increase power (other than by blocking), the researcher could increase the sample size. This reduces the standard error of the sampling distribution. With a smaller standard error, a test is more likely to be able to detect a difference in results from the two treatments, if such a difference exists. Part (b) is scored as follows: Essentially correct (E) if the student identifies a correct method for increasing power AND links the method to the mechanism for increasing power. Partially correct (P) if the student identifies a correct method for increasing power but fails to link the method to the mechanism for increasing power. Incorrect (I) if the student does not identify a correct method for increasing power. Note: Another correct method for increasing power is to increase the significance level, a. By increasing a, the researcher makes it easier to reject a false null hypothesis, which increases the power of the test. Please grade your answer as an AP Reader would.
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Multiple Choice:
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D)
Write a reflection on what you learned from doing this assignment. In addition, what answers did you get correct? What mistakes did you make? |
Ungraded Open Response: |
21) Problem #PRAE749 "PRAE749 - 146877 - 2009 AP® STA..." |
A)
2009 AP® STATISTICS FREE-RESPONSE QUESTIONS (Form B) STATISTICS SECTION II Part A Question 5 Spend about 0-65 minutes on this part of the exam. Percent of Section II score—75 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy and completeness of your results and explanations. 5. A bottle-filling machine is set to dispense 12.1 fluid ounces into juice bottles. To ensure that the machine is filling accurately, every hour a worker randomly selects four bottles filled by the machine during the past hour and measures the contents. If there is convincing evidence that the mean amount of juice dispensed is different from 12.1 ounces or if there is convincing evidence that the standard deviation is greater than 0.05 ounce, the machine is shut down for recalibration. It can be assumed that the amount of juice that is dispensed into bottles is normally distributed. During one hour, the mean number of fluid ounces of four randomly selected bottles was 12.05 and the standard deviation was 0.085 ounce. (a) Perform a test of significance to determine whether the mean amount of juice dispensed is different from 12.1 fluid ounces. Assume the conditions for inference are met. (b) To determine whether this sample of four bottles provides convincing evidence that the standard deviation of the amount of juice dispensed is greater than 0.05 ounce, a simulation study was performed. In the simulation study, 300 samples, each of size 4, were randomly generated from a normal population with a mean of 12.1 and a standard deviation of 0.05. The sample standard deviation was computed for each of the 300 samples. The dotplot below displays the values of the sample standard deviations. Use the results of this simulation study to explain why you think the sample provides or does not provide evidence that the standard deviation of the juice dispensed exceeds 0.05 fluid ounce. Answer questions a-b below, and/or in your notebook.
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Ungraded Open Response: |
B)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments". AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 5 Intent of Question The primary goals of this question were to assess students’ ability to (1) state the appropriate hypotheses, (2) identify and compute the appropriate test statistic, (3) make a conclusion in the context of the problem for a one-sample t test, and (4) use simulation results to find a simulated p-value to make an inference about the standard deviation. Solution Part (a): Step 1: State a correct pair of hypotheses.
Step 2: Identify a correct test (by name or by formula) and check appropriate conditions. (Stem of the question said to assume that conditions for inference are met.)
Step 3: Correct mechanics, including the value of the test statistic, df, and p-value (or rejection region).
Step 4: State a correct conclusion in the context of the problem, using the result of the computations. Because the p-value of 0.324 is larger than any reasonable significance level, such as a=.05, do not reject the null hypothesis that the mean number of fluid ounces being dispensed is 12.1 fluid ounces. There is not sufficient evidence to conclude that the machine is filling the juice bottles with an average amount different from 12.1 fluid ounces. Scoring This problem is scored in four sections. Section 1 consists of part (a), step 1. Section 2 consists of part (a), steps 2 and 3. Section 3 consists of part (a), step 4. Section 4 consists of part (b). Sections 1, 2, and 3 are each scored as essentially correct (E) or incorrect (I). Both step 2 and step 3 in section 2 must be completely correct to earn an E for section 2. Section 4 is scored as essentially correct (E), partially correct (P), or incorrect (I). Section 1 [part (a), step 1] is scored as follows: Essentially correct (E) if the student states a correct pair of hypotheses. Incorrect (I) otherwise. Section 2 [part (a), steps 2 and 3] is scored as follows: Essentially correct (E) if the student identifies a correct test (by name or formula) and includes correct mechanics. Incorrect (I) otherwise. Section 3 [part (a), step 4] is scored as follows: Essentially correct (E) if the student states a correct conclusion in the context of the problem. Incorrect (I) otherwise.
Notes: • If the p-value in section 2 is incorrect but the conclusion is consistent with the computed p-value, section 4 can be considered correct. Please grade your answer as an AP Reader would. |
Multiple Choice:
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C)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments". AP® STATISTICS 2009 SCORING GUIDELINES (Form B) Question 5 Intent of Question The primary goals of this question were to assess students’ ability to (1) state the appropriate hypotheses, (2) identify and compute the appropriate test statistic, (3) make a conclusion in the context of the problem for a one-sample t test, and (4) use simulation results to find a simulated p-value to make an inference about the standard deviation. Solution Part (b): In 300 simulated sample standard deviations, the value of the computed standard deviation (0.085) from our sample in part (a) or a value larger than 0.085 occurred only 12 times. This is a simulated p–value of 12 300 or 0.04. If the actual population standard deviation is 0.05, then we estimate that the chance of observing a sample standard deviation of 0.085 or larger is 4 percent. Because this simulated p-value is less than a significance level of 5 percent, the sample from part (a) provides strong evidence that the standard deviation of the juice being dispensed exceeds 0.05 ounces.
Scoring This problem is scored in four sections. Section 1 consists of part (a), step 1. Section 2 consists of part (a), steps 2 and 3. Section 3 consists of part (a), step 4. Section 4 consists of part (b). Sections 1, 2, and 3 are each scored as essentially correct (E) or incorrect (I). Both step 2 and step 3 in section 2 must be completely correct to earn an E for section 2. Section 4 is scored as essentially correct (E), partially correct (P), or incorrect (I). Section 4 [part (b)] is scored as follows: Essentially correct (E) if the student finds the correct simulated p-value from the dotplot or states that the actual standard deviation of 0.085 would be unusual if s=0.05 because 0.085 lies in the tail of the distribution AND an appropriate conclusion is made. Partially correct (P) if only the simulated p-value or statement that 0.085 lies in the tail is correct, but the conclusion is weak, wrong, or missing. Incorrect if the value 0.085 is not linked to the distribution. Notes: • In section 4, if both an aand a p-value are given together, the linkage between the p-value and the conclusion is implied. If no ais given, the solution must be explicit about the linkage by giving a correct interpretation of the p-value or explaining how the conclusion follows from the p-value. Please grade your answer as an AP Reader would.
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Multiple Choice:
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D)
Write a reflection on what you learned from doing this assignment. In addition, what answers did you get correct? What mistakes did you make? |
Ungraded Open Response: |
22) Problem #PRAE8BS "PRAE8BS - 147079 - " |
A)
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Ungraded Open Response: |
B)
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Ungraded Open Response: |
C)
Using these guidelines, how do you feel the AP readers would grade your response? |
Multiple Choice:
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D)
Using these guidelines, how do you feel AP readers would grade your response? |
Multiple Choice:
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E)
Using these guidelines, how do you feel AP readers would grade your response? |
Multiple Choice:
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F)
Finally, reflect on your answers. What have you learned about the AP test from this assignment? Do your answers need more detail or do you have to spend more time understanding the question? What will you take away from this to help you do good on the AP test? |
Ungraded Open Response: |
23) Problem #PRAE7MB "PRAE7MB - AP Question" |
A)
2008 Q2 STATISTICS SECTION II Part A Questions 1-5 Spend about 65 minutes on this part of the exam. Percent of Section II score—75
Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy and completeness of your results and explanations.
2. A local school board plans to conduct a survey of parents’ opinions about year-round schooling in elementary schools. The school board obtains a list of all families in the district with at least one child in an elementary school and sends the survey to a random sample of 500 of the families. The survey question is provided below. A proposal has been submitted that would require students in elementary schools to attend school on a year- round basis. Do you support this proposal? (Yes or No) The school board received responses from 98 of the families, with 76 of the responses indicating support for year-round schools. Based on this outcome, the local school board concludes that most of the families with at least one child in elementary school prefer year-round schooling.
(a) What is a possible consequence of nonresponse bias for interpreting the results of this survey?
(b) Someone advised the local school board to take an additional random sample of 500 families and to use the combined results to make their decision. Would this be a suitable solution to the issue raised in part (a) ? Explain.
(c) Suggest a different follow-up step from the one suggested in part (b) that the local school board could take to address the issue raised in part (a).
Answer questions a-c in your notebook. When you finish (and only when you are completely finished) type in "completed in notebook" and press submit. |
Exact Match (case sensitive):
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B)
Now, using the following information, grade yourself on how you think you did. Use the following answer and scoring as a guideline. AP® STATISTICS 2008 SCORING GUIDELINES Intent of Question: The primary goals of this question were to
assess a student’s ability to (1) identify a potential source of nonresponse
bias and recognize a possible consequence for interpreting the results of a
survey; (2) recognize that increasing sample size does not remove bias; and (3)
recommend an appropriate course of action to solve a practical problem with the
use of a survey. Solution Part (a): Responses were received from only 98 of the
500 (or 19.6 percent) of the randomly selected families. In other words, 80.4
percent of the randomly selected families did not respond to the survey. To
obtain a nearly unbiased estimate of the proportion of families with at least
one child in elementary school in this school district who support year-round
school, we would need to assume that the families that did not respond would
have a similar level of support for year-round school as those who did respond.
This would not be the case, for example, if families who support year-round
school were more likely to respond than families who do not support year-round
school. In such a case, the estimate of the proportion of families who support
year-round school calculated from the responses would tend to be higher than
the population proportion of families who favor year-round school. Scoring: Parts (a), (b), and (c) are each scored as
essentially correct (E), partially correct (P), or incorrect (I). Part (a) is
scored as follows: Essentially correct (E) if the student
clearly links the effect of nonresponse to biased estimation by explaining why
population support for year-round school would be overestimated (or
underestimated) from the sample results.
Partially correct (P) if the student
describes a reasonable consequence in the context of the study OR describes
a difference related to the issue between families who are likely to respond
and families who are not likely to respond.
Incorrect (I) otherwise.
Now, grade yourself according to the information given here. |
Multiple Choice:
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C)
Solution: Part (b): No, the nonresponse bias still exists. Combining the results from the original sample with a new random sample of 500 families will not solve the problem. Regardless of what happens in the second sample, the problem of nonresponse bias will still exist in the combined sample because there would be at least 402 nonresponses included from the original sample.
Scoring: Part (b) is scored as follows: Essentially correct (E) if the student says no, taking another sample will not solve the problem with nonresponse bias AND explains that nonresponse bias in the original sample would result in nonresponse bias in the combined sample regardless of the results from the second sample. Partially correct (P) if the student says no, taking another sample will not solve the problem with nonresponse bias, but provides a weak explanation OR says that the second sample will produce similar results to the first sample. Incorrect (I) if the student says yes, combining results from the original sample and a new random sample will solve the problem OR says no but provides no explanation or an incorrect argument OR does not respond to the question. Using this scoring guideline, grade yourself on how you think AP Readers would score your answer. |
Multiple Choice:
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D)
Solution: Part (c): Contact the 402 families from whom responses were not received and ask their opinion on the proposal. This may require additional mailings or telephone calls, but it will provide better information about support for year-round school among all families in the school district with at least one child in elementary school. OR Take a new random sample or take a census and use an alternative strategy, such as telephone calls or in- person interviews, to help increase the response rate.
Scoring:
Part (c) is scored as follows: Essentially correct (E) if the student provides an explicit description of a reasonable strategy for reducing nonresponse in a new survey or census or by following up with families who did not respond to the original study. Partially correct (P) if a student suggests that nonresponse should be reduced or response should be mandatory without providing an explicit description of a reasonable strategy. Incorrect (I) if the student does not provide a strategy to increase response rates or suggests a strategy that would result in other biases. 4 Complete Response OR All three parts essentially correct 3 Substantial Response OR Two parts essentially correct and one part partially correct 2 Developing Response OR Two parts essentially correct and no parts partially correct One part essentially correct and one or two parts partially correct Three parts partially correct
1 Minimal Response OR One part essentially correct and no parts partially correct No parts essentially correct and two parts partially correct
Based on the guideline, grade yourself how you think AP Readers would score your response to part c. |
Multiple Choice:
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E)
Write a reflection on what you learned from this assignment. For part a-c, what did you get right? What did you get wrong? |
Ungraded Open Response: |
24) Problem #PRAE68R "PRAE68R - 146024 - " |
A)
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Multiple Choice:
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Hints: |
Josephine μJ =16(0.1)+17(0.3)+18(0.4)+19(0.2)=17.7 Crystal μC = 17(0.45) + 18(0.4) + 19(0.15) = 17.7 |
B)
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Check All That Apply:
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Hints: |
J C Probability 16 17 (0.1)(0.45) = 0.045 17 18 (0.3)(0.40) = 0.12 18 19 (0.4)(0.15) = 0.06
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C)
ROUND answers to the nearest THOUSANDTHS. INCLUDE the zero... EX: 0.55 (Use answers from part b to help you figure out the answer) |
Exact Match (case sensitive):
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Hints: |
0.045 + 0.12 + 0.06 = 0.225 |
D)
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Multiple Choice:
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Hints: |
P(difference = –1) = 0.225 (from part c) P(difference = –2) = 1 – 0.015 – 0.225 – 0.325 – 0.260 – 0.90 = 0.085
The probability that Crystal’s score is higher than Josephine’s score is P(difference < 0) = 0.015 + 0.085 + 0.225 = 0.325 |
25) Problem #PRAE8F7 "PRAE8F7 - 2008 - Q4" |
A)
Do this problem in your notebook. Did you do it? |
Multiple Choice:
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B)
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Ungraded Open Response: |
C)
Have 4 decimal places. |
Algebraic Expression:
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D)
Did you check your work? |
Multiple Choice:
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E)
Given the guidelines above, how would an AP grader grade your part a? |
Multiple Choice:
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F)
Given the guidelines above, how would an AP grader grade your part b? |
Algebraic Expression:
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G)
Given the guidelines above, how would an AP grader grade your part c? |
Multiple Choice:
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26) Problem #PRA5T9 "PRA5T9 - " |
Multiple Choice: |
27) Problem #PRAE7NS "PRAE7NS - 146428 - " |
A)
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Multiple Choice:
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B)
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Multiple Choice:
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C)
Which of statistics C or D would be a better estimator of the population parameter? |
Algebraic Expression:
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28) Problem #PRAE7X9 "PRAE7X9 - 146722 - " |
A)
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Multiple Choice:
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B)
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Ungraded Open Response: |
29) Problem #PRAE7YM "PRAE7YM - 146733 - " |
A)
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Ungraded Open Response: |
B)
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Ungraded Open Response: |
30) Problem #PRAE7YY "PRAE7YY - 146744 - Format your answ..." |
A)
Format your answer thus: normal / not normal, mean, standard deviation |
Algebraic Expression:
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B)
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Multiple Choice:
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C)
Answer in minutes. |
Algebraic Expression:
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31) Problem #PRAE69W "PRAE69W - 146060 -AP Question- 2009-Question 3" |
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Ungraded Open Response: |
Hints: |
b) Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
32) Problem #PRAE78Q "PRAE78Q - 146984 - 2007 AP Statistic..." |
A)
2007 AP Statistics Free-Response Question #1 Statistics Part A Question #1 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as the accuracy and completenss of your answers and explanations. . p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 18.0px 'Trebuchet MS'} For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done.
How do you think the AP readers would grade you on part (a)? |
Multiple Choice:
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C)
How do you think the AP reader would grade your answer for part (b)? |
Multiple Choice:
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D)
How do you think the AP reader would grade your answer for part (c)?
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Multiple Choice:
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33) Problem #PRAE74M "PRAE74M - 146857 - For this&..." |
A)
For this question, answer it in your notebook just as you would if you were taking the AP exam. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Write a reflection on what you learned from this assignment. For this AP question what did you do right? what did you do wrong ? |
Ungraded Open Response: |
34) Problem #PRAE7ZW "PRAE7ZW - 146773 - For these four q..." |
A)
For these four questions, answer them in your notebook as you would on the AP exam. After you answer the questions in your notebook, click I have completed the answer in my notebook. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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E)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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F)
Write a reflection on what you learned from this assignment. For these 4 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
35) Problem #PRAE72V "PRAE72V - 146803 - Fo..." |
A)
For these 5 questions, answer them in your notebook just as you would if you were taking the AP exam. completed assignment in notebook and hit submit. |
Multiple Choice:
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B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Algebraic Expression:
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E)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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F)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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G)
Write a reflection on what you learned from this assignment. For these 5 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
36) Problem #PRAE7NC "PRAE7NC - 146415 - STA..." |
A)
STATISTICS SECTION II Part A Questions 1 Spend about 65 minutes on this part of the exam. Percent of Section II grade—75 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as on the accuracy and completeness of your results and explanations.
1. The Better Business Council of a large city has concluded that students in the city’s schools are not learning enough about economics to function in the modern world. These findings were based on test results from a random sample of 20 twelfth-grade students who completed a 46-question multiple-choice test on basic economic concepts. The data set below shows the number of questions that each of the 20 students in the sample answered correctly.
12 16 18 17 18 33 41 44 38 35 19 36 19 13 43 8 16 14 14 9
(a) Display these data in a stemplot. (b) Use your stemplot from part (a) to describe the main features of this score distribution. (c) Why would it be misleading to report only a measure of center for this score distribution? Answer these three questions in your notebook as you would if you were taking the AP exam. |
Multiple Choice:
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B)
Solution: Question 1 The three primary goals of this question are to assess a student’s ability to: (1) construct a stemplot from a given data set; (2) describe the important features of the plot; and (3) discuss how a single measure of centrality fails to convey important features of the plot. Solution Part (a): 0| 89 1| 26878993640 2| 3| 3856 4| 143 Legend: 1| 2 represents 12 questions answered correctly OR, with ordered leaves (not required) 0| 89 1| 02346678899 2| 3| 3568 4| 134 Legend: 1| 2 represents 12 questions answered correctly OR, with repeated stems (leaves may be ordered or not) 0H 89 1L 0234 1H 6678899 2L 2H 3L 3 3H 568 4L 134
Legend: 3H 6 represents 36 questions answered correctly 4L 1 represents 41 questions answered correctly
Scoring
Part (a) is scored as either essentially correct (E) or incorrect (I). Part (a) is essentially correct (E) if in part (a) the student gives a correctly constructed stemplot. Any other type of plot is incorrect (I). NOTE: One or two misplaced or omitted leaves can still be considered essentially correct as long as the important features of the display are not altered.
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Multiple Choice:
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C)
Solution: Part (b): The most striking feature of the plot is that the scores cluster into two groups, one concentrated in the mid-teens and the other in the high 30s (or one with relatively low scores on the exam and one with relatively high scores). There are no scores in the 20s.
Part (c): A measure of center might fall between the two groups (as does the mean of 22.95 here) where there is no data and would not provide an accurate picture of student performance on the exam. It would not indicate that students tended to score either very well or very poorly on the exam.
Scoring:
Score Parts B and C together based on the following guidelines.
Section 2 is essentially correct (E) if in either part (b) or (c) the student clearly notices: 1.that there are two groups; 2.that there is a gap in the middle of the distribution; 3.the relative or specific positions of the two groups, OR the location of the gap, OR a general measure of location (such as mean, median, or the fact that most scores fall between 10 and 19). (Median = 18, mean = 22.95) Section 2 is partially correct (P) if the student notes two out of the three. Section 3 is essentially correct (E) if in part (b) or part (c) the solution is given in the context of the problem and is communicated well. Section 3 is partially correct (P) if the student mentions the context (for instance, using the word “scores”), but communication of the context is weak. Section 3 is incorrect (I) if the context is not mentioned at all. Section 4 is essentially correct (E) if in part (c) a valid reason is given for why a measure of center is not sufficient for data of this type (with the two groups and a gap). If, for instance, the reasoning would apply equally well to other shapes, it is not sufficient. Section 4 can be at most partially correct (P) if a student does not recognize the groups or gap. It is partially correct if the student compares the mean and median and cites outliers or skewness as the reason why a measure of center is not sufficient, or if a general reason is given for why a measure of center is not sufficient. (For instance, the student may say that center alone without some measure of spread is never sufficient.) |
Multiple Choice:
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D)
Reflect on this AP question- what answers did you get right? What mistakes did you make? |
Ungraded Open Response: |
37) Problem #PRAE68S "PRAE68S - 146025 - Round answers to ..." |
A)
Round answers to the nearest hundredths. Include the zero. Ex: 0.55 |
Exact Match (case sensitive):
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Hints: |
P(X >3) = 0.07 + 0.04 + 0.04 + 0.02 = 0.17. |
B)
Round answers to the nearest ten thousandths. Include
the zero. Ex: 0.55 |
Exact Match (case sensitive):
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Hints: |
Y = number of households in violation. Y has a binomial distribution with n = 10 and p = 0.17.
P(Y=2)= (10 choose 2)(0.17)^2(0.83)^8 =0.2929. |
C)
|
Multiple Choice:
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Hints: |
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38) Problem #PRA5WF "PRA5WF - 25580 - Comparing_and_Scaling_2_4_a_Worked" |
In the after school program at the local elementary school there were three rooms of kids. The red room, the Green room and the Yellow room. There were 9 kids in the Red room and they got to share 4 big chocolate bars. There were 11 kids in the Green room and they shared 5 big chocolate bars. There were 15 kids in the Yellow room and they got to share 7 big chocolate bars. The chocolate bars in each room were shared equally. In which room did the kids get the most chocolate? |
Multiple Choice:
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Scaffold:
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Scaffold:
|
39) Problem #PRAE7S4 "PRAE7S4 - 146562 - For these quest..." |
A)
For these questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
F)
Write a reflection on what you learned from this assignment. For these questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
40) Problem #PRAE7TF "PRAE7TF - 146573 - For this questio..." |
A)
For this question, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Now, using the following information, please grade your own response to see how you would have done. Use the following answer and scoring guidelines to grade your response. Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
F)
Write a reflection on what you learned from this assignment. For these questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
41) Problem #PRAE7SW "PRAE7SW - 146556 - For these 3 ques..." |
A)
For these 3 questions, answer them in your notebook as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes on in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Using the provided scoring guideline, how do you feel the AP readers would grade your response? |
Multiple Choice:
|
C)
Write a reflection on what you learned from this assignment.What did you do right? What did you do wrong? |
Ungraded Open Response: |
42) Problem #PRAE7VK "PRAE7VK - 146639 - These pro..." |
These problems should be answered in your notebook. |
Multiple Choice:
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43) Problem #PRAE7VM "PRAE7VM - 146640 - These problems s..." |
These problems should be answered in your notebook. |
Multiple Choice:
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44) Problem #PRAE7VR "PRAE7VR - 146644 - These problems s..." |
These problems should be answered in your notebook. |
Multiple Choice:
|
45) Problem #PRAE7YE "PRAE7YE - Term II Extra Credit" |
A)
Answer the following parts in your notebook, including any diagrams. Show your work! |
Multiple Choice:
|
B)
Using the provided scoring guidelines, how do you feel the AP readers would grade your response? |
Multiple Choice:
|
C)
Write a short reflection on how this activity helped you and what you learned. |
Ungraded Open Response: |
46) Problem #PRAE7UU "PRAE7UU - 146616 - " |
A)
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Ungraded Open Response: |
B)
Based on the Scoring Guidelines, how do you think AP Readers would grade your response? |
Multiple Choice:
|
C)
Based on the Scoring Guidelines, how do you think AP Readers would grade your response? |
Multiple Choice:
|
D)
Based on the Scoring Guidelines, how do you think AP Readers would grade your response? |
Multiple Choice:
|
E)
Based on the Scoring Guidelines, how do you think AP Readers would grade your response? |
Multiple Choice:
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47) Problem #PRA5YG "PRA5YG - 25643 - Stretching_and_Shrinking_Inv_3_4_b_Hints" |
If we know the area of ABCD is 16 times that of KLMN, and the two parallelograms are similar, what is the measure of BC? (Picture is not drawn to scale) |
Algebraic Expression:
|
Hints: |
|
|
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4 * 7 = 28. Please, type in 28 |
48) Problem #PRAE8FA "PRAE8FA - 147188 - " |
A)
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Algebraic Expression:
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B)
|
Algebraic Expression:
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C)
|
Algebraic Expression:
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49) Problem #PRAE8FC "PRAE8FC - 147190 - " |
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Ungraded Open Response: |
50) Problem #PRAE8FE "PRAE8FE - 147192 - " |
A)
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Ungraded Open Response: |
B)
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Ungraded Open Response: |
C)
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Ungraded Open Response: |
D)
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Ungraded Open Response: |
51) Problem #PRAE8FF "PRAE8FF - 147193 - Andrew is shootin..." |
Andrew is shooting hoops. What is the probability that he shoots more than 6 times before he gets it in? Round to the nearest hundredth. |
Algebraic Expression:
|
52) Problem #PRA5U6 "PRA5U6 - 25540 - Moving_Straight_Ahead_Inv_2_4_b_hints" |
Booker T. Washington Middle School found two companies that would deliver healthy snacks to their school. The tables below show the cost for each company.
|
Algebraic Expression:
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Hints: |
|
Take a look at this image. |
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53) Problem #PRAE8FN "PRAE8FN - 147199 - " |
A)
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Ungraded Open Response: |
B)
Now, review the information below, and grade your response as an AP Reader would. NOTE: If you want to see what you submitted as an answer, simply open another tutor tab in another window. Then, click on "Show Item Report", rather than "Show Assignments". Please grade your answer as an AP Reader would. |
Multiple Choice:
|
C)
Write a reflection on what you learned from doing this assignment. In addition, what answers did you get correct? What mistakes did you make? |
Ungraded Open Response: |
54) Problem #PRAE8FY "PRAE8FY - 147209 - &nb..." |
A)
For these 4 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
F)
Write a reflection on what you learned from this assignment. For these 4 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
55) Problem #PRAE8FZ "PRAE8FZ - 147210 - This question ha..." |
A)
This question has an open response component with four parts. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
F)
Write a reflection on what you learned from this assignment. For these 4 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
56) Problem #PRAE8F2 "PRAE8F2 - 147211 - For these 3 que..." |
A)
For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Write a reflection on what you learned from this assignment. For these 3 AP questions what did you do right? What did you do wrong? |
Ungraded Open Response: |
57) Problem #PRAE7VY "PRAE7VY - 146651 - AP QUESTION - 2005 FORM B - QUESTION 1" |
A)
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Ungraded Open Response: |
B)
|
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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58) Problem #PRAE7W8 "PRAE7W8 - 146690 - AP QUESTION - 2005 FORM B - QUESTION 2" |
A)
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Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
59) Problem #PRAE7XW "PRAE7XW - 146711 - AP QUESTION - 2005 FORM B - QUESTION 3" |
A)
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Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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60) Problem #PRAE7YK "PRAE7YK - 146732 - AP QUESTION - 2005 FORM B - QUESTION 4" |
A)
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Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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61) Problem #PRAE7YQ "PRAE7YQ - 146736 - AP QUESTION - 2005 FORM B - QUESTION 5" |
A)
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Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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62) Problem #PRAE7YW "PRAE7YW - 146742 - AP QUESTION - 2005 FORM B - QUESTION 6" |
A)
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Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
D)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
E)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
63) Problem #PRAE7UA "PRAE7UA - 146599 - " |
A)
|
Ungraded Open Response: |
B)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
|
C)
Using the provided scoring guidelines, how do you feel the AP Readers would grade your response? |
Multiple Choice:
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64) Problem #PRAE8E7 "PRAE8E7 - 147185 - " |
A)
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Ungraded Open Response: |
B)
|
Ungraded Open Response: |
C)
|
Ungraded Open Response: |
D)
Using the provided scoring guidelines, how do you feel the AP Readers would have graded your response? |
Multiple Choice:
|
E)
Using the provided scoring guidelines, how do you think the AP Readers would have graded your response? |
Multiple Choice:
|
F)
Using the given scoring guide, how do you think the AP Readers would score your response? |
Multiple Choice:
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G)
Reflection: |
Ungraded Open Response: |
65) Problem #PRAE8SX "PRAE8SX - 147518 - For these ..." |
A)
For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
For each part of question 3, grade yourself on what you believe a person grading the test would have given you. Either an Essentially (E), Partially (P), or Incorrect (I). |
Ungraded Open Response: |
C)
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Ungraded Open Response: |
D)
|
Ungraded Open Response: |
E)
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Ungraded Open Response: |
66) Problem #PRAE8S2 "PRAE8S2 - 147521 - For these 3 ques..." |
A)
For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
For each part of question 3, grade yourself on what you believe a person grading the test would have given you. Either an Essentially (E), Partially (P), or Incorrect (I). |
Ungraded Open Response: |
C)
|
Ungraded Open Response: |
D)
|
Ungraded Open Response: |
67) Problem #PRAE8F9 "PRAE8F9 - 147218 - 2004 Q5" |
A)
Do this problem in your notebook and write whether or not you accept the value and explain your results. |
Ungraded Open Response: |
B)
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Ungraded Open Response: |
C)
|
Multiple Choice:
|
D)
|
Multiple Choice:
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68) Problem #PRAE8GB "PRAE8GB - 147220 - For these 3 ques..." |
A)
For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button |
Ungraded Open Response: |
B)
now review your answers... |
Ungraded Open Response: |
C)
|
Ungraded Open Response: |
An error occured while attempting to print problem 146846
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70) Problem #PRAE74X "PRAE74X - 146867 - When a law firm r..." |
A)
When a law firm represents a group of people in a class action lawsuit and wins that lawsuit, the firm receives a percentage of the group's monetary settlement. That settlement amount is based on the total number of people in the group - the larger the group and the larger the settlement, the more money the firm will receive. A law firm is trying to decide whether to represent car owners in a class action lawsuit against the manufacturer of a certain make and model for a particular defect. If 5 percent or less of the cars of this make and model have the defect, the firm will not recover its expenses. Therefore, the firm will handle the lawsuit only if it is convinced that more than 5 percent of cars of this make and model have the defect, The firm plans to take a random sample of 1000 people who bought this car and ask them is they experienced the defect in their cars. a. Define the parameter of interest and state the null and alternative hypotheses that the law firm should test. |
Ungraded Open Response: |
B)
b. In the context of this situation, describe Type I and Type II errors and describe the consequences of each of these for the law firm. |
Ungraded Open Response: |
71) Problem #PRAE743 "PRAE743 - 146871 - Men's shirt sizes..." |
A)
Men's shirt sizes are determined by their neck sizes. Suppose that men's neck sizes are approximately normally distributed 15.7 inches and standard deviation 0.7 inch. A retailer sells men's shirts in sizes S,M,L,XL, where the shirt sizes are defined in the table below. a. Because the retailer only stocks the sizes listed above, what proportion of customers will find that the retailer does not carry any shirts in their sizes? Show your work.
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Algebraic Expression:
|
B)
b. Using a sketch of a normal curve, illustrate the proportion of men whose shirt size is M. Calculate this proportion. |
Algebraic Expression:
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C)
c. Of 12 randomly selected customers, what is the probability that exactly 4 will request size M? Show your work. |
Algebraic Expression:
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72) Problem #PRAE8E5 "PRAE8E5 - 147183 - Because of concer..." |
A)
Because of concerns about employee stress, a large company is conducting a study to compare two programs (tai chi or yoga) that may help employees reduce their stress levels. Tai chi is a 1200 year old practice, originating in China that consists of slow, fluid movements. Yoga is a practice, originating in India that consists of breathing exercises and movements designed to stretch and relax muscles. The company has assembled a group of volunteer employees to participate in the study during the first half of their lunch hour each day for a 10-week period. Each volunteer will be assigned at random to one of the two programs. Volunteers will have their stress levels measured just before beginning the program and 10 weeks later at the completion of it. a. A group of volunteers who work together ask to be assigned to the same program so that they can participate in that program together. Give an example of a problem that might arise if this is permitted. Explain to this volunteer group why random assignment to the two programs will address this problem. |
Ungraded Open Response: |
B)
b. Someone proposes that a control group be included in the design as well. The stress level would be measured for each volunteer assigned to the control group at the start of the study and again 10 weeks later. What additional information, if any, would this provide about the effectiveness of the two programs? |
Ungraded Open Response: |
C)
c. Is it reasonable to generalize the findings of this study to all employees of this company? Explain. |
Ungraded Open Response: |
73) Problem #PRAE75E "PRAE75E - 146882 - A random sample o..." |
A random sample of 200 students was selected from a large college in the United States. Each selected student was asked to give his or her opinion on the following statement: "The most important quality of a person who aspires to be the PResident of the United States is a konwledge of foreign affairs." Each response was recorded in one of five catogories. the gender of each selected student was noted. The data are summarized in the table below. Is there sufficient evidence to indicate that the response is dependent on gender? Provide statistical evidence to support your conclusion. Response Category Strongly Somewhat Somewhat Strongly Disagree Disagree Neither Agree Agree
|
Ungraded Open Response: |
74) Problem #PRAE8GU "PRAE8GU - 147236 - 2003 AP Statisti..." |
A)
2003 AP Statistics Free-Response Question #6 Statistics Part B Question #6 Directions: Show all your work. Indicate clearly the methods you use, because you will be graded on the correctness of your methods as well as the accuracy and completenss of your answers and explanations. For these 3 questions, answer them in your notebook just as you would if you were taking the AP exam. This question has an open response component. This is an option for the teacher to use, if specific instructions are given to the student. If no instructions are given on what goes in the open response. Just type - completed assignment in notebook and hit submit. After you are finished, AND ONLY AFTER YOU ARE FINISHED, click the submit button. |
Ungraded Open Response: |
B)
Now, using the following information, please grade your own response to see how you would have done. How do you think the AP readers would grade you on part a? |
Multiple Choice:
|
C)
Now, using the following information, please grade your own response to see how you would have done. How do you think an AP reader would grade your answer? |
Multiple Choice:
|
D)
Now, using the following information, please grade your own response to see how you would have done. How do you think an AP reader would grade you on part c? |
Multiple Choice:
|
E)
Now, using the following information, please grade your own response to see how you would have done. How do you think an AP reader would grade your answer to part d? |
Multiple Choice:
|
75) Problem #PRAE6RA "PRAE6RA - 145545 - A teacher wishes ..." |
A teacher wishes to know whether the males in his/her class have more conservative attitudes than the females. A questionnaire is distributed assessing attitudes and the males and the females are compared. Is this an example of descriptive or inferential statistics? |
Ungraded Open Response: |
76) Problem #PRAE6RB "PRAE6RB - 145546 - A cognitive psych..." |
A cognitive psychologist is interested in comparing two ways of presenting stimuli on subsequent memory. Twelve subjects are presented with each method and a memory test is given. What would be the roles of descriptive and inferential statistics in the analysis of these data? |
Ungraded Open Response: |
77) Problem #PRAE6RC "PRAE6RC - 145547 - If you are told t..." |
If you are told that you scored in the 80th percentile, from just this information would you know exactly what that means and how it was calculated? Explain. |
Ungraded Open Response: |
78) Problem #PRAE6RE "PRAE6RE - 145549 - A study is conduc..." |
A study is conducted to determine whether people learn better with spaced or massed practice. Subjects volunteer from an introductory psychology class. At the beginning of the semester 12 subjects volunteer and are assigned to the massed-practice condition. At the end of the semester 12 subjects volunteer and are assigned to the spaced-practice condition. This experiment involves two kinds of non-random sampling: (1) Subjects are not randomly sampled from some specified population and (2) Subjects are not randomly assigned to conditions. Which of the problems relates to the generality of the results? Which of the problems relates to the validity of the results? Which problem is more serious? |
Ungraded Open Response: |
79) Problem #PRAE6RF "PRAE6RF - 145550 - Give an example o..." |
Give an example of an independent and a dependent variable. |
Ungraded Open Response: |
80) Problem #PRAE6RG "PRAE6RG - 145551 - Categorize the f..." |
Categorize the following variables as being qualitative or quantitative:Rating of the quality of a movie on a 7-point scale |
Ungraded Open Response: |
81) Problem #PRAE6RH "PRAE6RH - 145552 - Which of the fol..." |
Which of the following are linear transformations?Converting from meters to kilometers |
Ungraded Open Response: |
82) Problem #PRAE6RJ "PRAE6RJ - 145553 - The formula for f..." |
The formula for finding each student's test grade (g) from his or her raw score (s) on a test is as follows: g = 16 + 3s If a student got a raw score of 20, what is his test grade? |
Algebraic Expression:
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83) Problem #PRAE6RK "PRAE6RK - 145554 - For the numbers ..." |
For the numbers 1, 2, 4, 16, compute the following:ΣX |
Ungraded Open Response: |
84) Problem #PRAE6RM "PRAE6RM - 145555 - If you wanted to..." |
If you wanted to conduct a study about the relationship between the amount of television watched a day and sports participation in children, which of the following two choices (a or b) would be the better way of asking that question?a) Check the best description of how much television you watch per day: |
Ungraded Open Response: |
85) Problem #PRAE6RN "PRAE6RN - 145556 - Which of the freq..." |
Which of the frequency polygons has a large positive skew? Which has a large negative skew? |
Ungraded Open Response: |
86) Problem #PRAE6RQ "PRAE6RQ - 145558 - What is more like..." |
What is more likely to have a skewed distribution: time to solve an anagram problem (where the letters of a word or phrase are rearranged into another word or phrase like "dear" and "read" or "funeral" and "real fun") or scores on a vocabulary test? |
Ungraded Open Response: |
87) Problem #PRAE73H "PRAE73H - 146823 - Name some ways to..." |
Name some ways to graph quantitative variables and some ways to graph qualitative variables. |
Ungraded Open Response: |
88) Problem #PRAE73V "PRAE73V - 146834 - Based on the freq..." |
Based on the frequency polygon displayed below, the most common test grade was around what score? Explain. |
Ungraded Open Response: |
89) Problem #PRAE736 "PRAE736 - 146843 - An experiment com..." |
An experiment compared the ability of three groups of participants to remember briefly presented chess positions. The data are shown below. The numbers represent the total number of pieces correctly remembered from three chess positions. Create side-by-side box plots for these three groups in your notebooks. What can you say about the differences between these groups from the box plots? |
Ungraded Open Response: |
90) Problem #PRAE74D "PRAE74D - 146850 - You have to decid..." |
You have to decide between displaying your data with a histogram or with a stem and leaf display. What factor(s) would affect your choice? |
Ungraded Open Response: |
91) Problem #PRAE74E "PRAE74E - 146851 - In a box plot, wh..." |
In a box plot, what percent of the scores are between the lower and upper hinges? |
Ungraded Open Response: |
92) Problem #PRAE74G "PRAE74G - 146853 - A student has dec..." |
A student has decided to display the results of his project on the number of hours people in various countries slept per night. He compared the sleeping patterns of people from the US, Brazil, France, Turkey, China, Egypt, Canada, Norway, and Spain. He was planning on using a line graph to display this data. Is a line graph appropriate? What might be a better choice for a graph? |
Ungraded Open Response: |
93) Problem #PRAE74H "PRAE74H - 146854 - For the data from..." |
For the data from the 1977 Stat. and Biom. 200 class for eye color, construct in your notebook: a. Pie graph b. Horizontal bar graph c. vertical bar graph d. a frequency table with the relative frequency of each eye color |
Ungraded Open Response: |
94) Problem #PRAE74K "PRAE74K - 146856 - A graph appears b..." |
A graph appears below showing the number of adults and children who prefer each type of soda. There were 130 adults and kids surveyed. Discuss some ways in which the graph below could be improved. |
Ungraded Open Response: |
95) Problem #PRAE74N "PRAE74N - 146858 - Which of the box ..." |
Which of the box plots below has a large positive skew? Which has a large negative skew? |
Ungraded Open Response: |
96) Problem #PRAE7ET "PRAE7ET - 146212 - Make up a dataset..." |
Make up a dataset of 12 numbers with a positive skew. Use a statistical program to compute the skew. Is the mean larger than the median as it usually is for distributions with a positive skew? What is the value for skew? |
Ungraded Open Response: |
97) Problem #PRAE7EU "PRAE7EU - 146213 - Repeat Problem 1 ..." |
Repeat Problem 1 only this time make the dataset have a negative skew |
Ungraded Open Response: |
98) Problem #PRAE7EW "PRAE7EW - 146215 - Make up three dat..." |
Make up three data sets with 5 numbers each that have: (a) the same mean but different standard deviations (b) the same mean but different medians (c) the same median but different means |
Ungraded Open Response: |
99) Problem #PRAE7EX "PRAE7EX - 146216 - Find the mean an..." |
Find the mean and median for the following three variables: A B C 8 4 6 5 4 2 7 6 3 1 3 4 3 4 1 |
Algebraic Expression: |
100) Problem #PRAE7EY "PRAE7EY - 146217 - A sample of 30 di..." |
A sample of 30 distance scores measured in yards has a mean of 7, a variance of 16, and a standard deviation of 4. (a) You want to convert all your distances from yards to feet, so you multiply each score in the sample by 3. What are the new mean, variance, and standard deviation? (b) You then decide that you only want to look at the distance past a certain point. Thus, after multiplying the original scores by 3, you decide to subtract 4 feet from each of the scores. Now what are the new mean, variance, and standard deviation? |
Algebraic Expression: |
101) Problem #PRAE7EZ "PRAE7EZ - 146218 - You recorded the ..." |
You recorded the time in seconds it took for 8 participants to solve a puzzle. These times appear below. However, when the data was entered into the statistical program, the score that was supposed to be 22.1 was entered as 21.2. You had calculated the following measures of central tendency: the mean, the median, and the mean trimmed 25%. Which of these measures of central tendency will change when you correct the recording error? 15.2 18.8 19.3 19.7 20.2 21.8 22.1 29.4 |
Algebraic Expression: |
102) Problem #PRAE7E2 "PRAE7E2 - 146219 - For the test scor..." |
For the test scores in question #6, which measures of variability (range, standard deviation, variance) would be changed if the 22.1 data point had been erroneously recorded as 21.2? |
Algebraic Expression: |
103) Problem #PRAE7E3 "PRAE7E3 - 146220 - You know the mini..." |
You know the minimum, the maximum, and the 25th, 50th, and 75th percentiles of a distribution. Which of the following measures of central tendency or variability can you determine? mean, median, mode, trimean, geometric mean, range, interquartile range, variance, standard deviation |
Algebraic Expression: |
104) Problem #PRAE7E4 "PRAE7E4 - 146221 - For the numbers 1..." |
For the numbers 1, 3, 4, 6, and 12: 1. Find the value (v) for which Σ(X-v)2 is minimized. 2. Find the value (v) for which S |x-v| is minimized. |
Algebraic Expression: |
105) Problem #PRAE7E5 "PRAE7E5 - 146222 - Your younger brot..." |
Your younger brother comes home one day after taking a science test. He says that someone at school told him that "60% of the students in the class scored above the median test grade." What is wrong with this statement? What if he said "60% of the students scored below the mean?" |
Algebraic Expression: |
106) Problem #PRAE7E6 "PRAE7E6 - 146223 - An experiment com..." |
An experiment compared the ability of three groups of participants to remember briefly-presented chess positions. The data are shown below. The numbers represent the number of pieces correctly remembered from three chess positions. Compare the performance of each group. Consider spread as well as central tendency.
|
Algebraic Expression: |
107) Problem #PRAE7FA "PRAE7FA - 146227 - True/False: A bim..." |
True/False: A bimodal distribution has two modes and two medians. |
Algebraic Expression: |
108) Problem #PRAE7FB "PRAE7FB - 146228 - True/False: The b..." |
True/False: The best way to describe a skewed distribution is to report the mean |
Algebraic Expression: |
109) Problem #PRAE7FC "PRAE7FC - 146229 - True/False: When ..." |
True/False: When plotted on the same graph, a distribution with a mean of 50 and a standard deviation of 10 will look more spread out than will a distribution with a mean of 60 and a standard deviation of 5 |
Algebraic Expression: |
110) Problem #PRAE7FD "PRAE7FD - 146230 - Compare the mean,..." |
Compare the mean, median, trimean in terms of their sensitivity to extreme scores |
Algebraic Expression: |
111) Problem #PRAE7FE "PRAE7FE - 146231 - If the mean time ..." |
If the mean time to respond to a stimulus is much higher than the median time to respond, what can you say about the shape of the distribution of response times? |
Algebraic Expression: |
112) Problem #PRAE7FF "PRAE7FF - 146232 - A set of numbers ..." |
A set of numbers is tranformed by taking the log base 10 of each number. The mean of the transformed data is 1.65. What is the geometric mean of the untransformed data? |
Algebraic Expression: |
113) Problem #PRAE7FG "PRAE7FG - 146233 - Which measure of ..." |
Which measure of central tendency is most often used for returns on investment? |
Algebraic Expression: |
114) Problem #PRAE7FH "PRAE7FH - 146234 - The histogram is ..." |
The histogram is in balance on the fulcrum. What are the mean, median, and mode of the distribution (approximate where necessary)? /images/assistments/22731.jpg The original GIF version can be accessed at: /images/assistments/22731-original.gif |
Algebraic Expression: |
115) Problem #PRAE8KU "PRAE8KU - Problem #147329" |
Describe the relationship between variables A and C. Think of things these variables could represent in real life. ( |
Algebraic Expression: |
116) Problem #PRAE8JM "PRAE8JM - 147291 - Make up a data se..." |
Make up a data set with 10 numbers that has a positive correlation. |
Algebraic Expression: |
117) Problem #PRAE8JQ "PRAE8JQ - 147294 - Make up a data se..." |
Make up a data set with 10 numbers that has a negative correlation. |
Algebraic Expression: |
118) Problem #PRAE8JS "PRAE8JS - 147296 - If the correlatio..." |
If the correlation between weight (in pounds) and height (in feet) is 0.58, find: (a) the correlation between weight (in pounds) and height (in yards) (b) the correlation between weight (in kilograms) and height (in meters). |
Algebraic Expression: |
119) Problem #PRAE8JT "PRAE8JT - 147297 - Would you expect ..." |
Would you expect the correlation between High School GPA and College GPA to be higher when taken from your entire high school class or when taken from only the top 20 students? Why? |
Algebraic Expression: |
120) Problem #PRAE8JU "PRAE8JU - 147298 - For a certain cla..." |
For a certain class, the relationship between the amount of time spent studying and the test grade earned was examined. It was determined that as the amount of time they studied increased, so did their grades. Is this a positive or negative association? |
Algebraic Expression: |
121) Problem #PRAE8J4 "PRAE8J4 - 147306 - For this same cla..." |
For this same class, the relationship between the amount of time spent studying and the amount of time spent socializing per week was also examined. It was determined that the more hours they spent studying, the fewer hours they spent socializing. Is this a positive or negative association? |
Algebraic Expression: |
122) Problem #PRAE8J6 "PRAE8J6 - 147308 - For the following..." |
A)
For the following data:
|
Algebraic Expression: |
B)
Find the deviation scores for Variable B that correspond to the raw scores of 5 and 4. |
Algebraic Expression: |
C)
Just from looking at these scores, do you think these variable A and B are positively or negatively correlated? Why? |
Algebraic Expression: |
D)
Now calculate the correlation. Were you right? |
Algebraic Expression: |
123) Problem #PRAE8KA "PRAE8KA - 147312 - Students took two..." |
Students took two parts of a test, each worth 50 points. Part A has a variance of 25, and Part B has a variance of 36. The correlation between the test scores is 0.8. (a) If the teacher adds the grades of the two parts together to form a final test grade, what would the variance of the final test grades be? (b) What would the variance of Part A - Part B be? |
Algebraic Expression: |
124) Problem #PRAE8KC "PRAE8KC - 147314 - The correlation i..." |
The correlation in real life between height and weight is r=1. |
Multiple Choice:
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125) Problem #PRAE8KF "PRAE8KF - 147317 - It is possible fo..." |
It is possible for variables to have r=0 but still have a strong association. |
Multiple Choice:
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126) Problem #PRAE8KH "PRAE8KH - 147319 - Two variables wit..." |
Two variables with a correlation of 0.3 have a stronger linear relationship than two variables with a correlation of -0.7. |
Multiple Choice:
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127) Problem #PRAE8KM "PRAE8KM - 147322 - After polling a c..." |
After polling a certain group of people, researchers found a 0.5 correlation between the number of car accidents per year and the driver's age. This means that older people get in more accidents. |
Multiple Choice:
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128) Problem #PRAE8KN "PRAE8KN - 147323 - The correlation b..." |
The correlation between R and T is the same as the correlation between T and R. |
Multiple Choice:
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129) Problem #PRAE8KQ "PRAE8KQ - 147325 - To examine bivari..." |
To examine bivariate data graphically, the best choice is two side by side histograms. |
Multiple Choice:
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130) Problem #PRAE8KT "PRAE8KT - 147328 - A correlation of ..." |
A correlation of r=1.2 is not possible. |
Multiple Choice:
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131) Problem #PRAE8R3 "PRAE8R3 - 147491 - What is the proba..." |
A)
What is the probability of rolling a pair of dice and obtaining a total score of 9 or more? |
Algebraic Expression: |
B)
What is the probability of rolling a pair of dice and obtaining a total score of 7? |
Algebraic Expression: |
132) Problem #PRAE8R4 "PRAE8R4 - 147492 - A box contains fo..." |
A)
A box contains four black pieces of cloth, two striped pieces, and six dotted pieces. A piece is selected randomly and then placed back in the box. A second piece is selected randomly. What is the probability that both pieces are dotted? |
Algebraic Expression: |
B)
What is the probability that the first piece is black and the second piece is dotted? |
Algebraic Expression: |
C)
What is the probability that one piece is black and one piece is striped? |
Algebraic Expression: |
133) Problem #PRAE8R5 "PRAE8R5 - 147493 - A card is drawn a..." |
A)
A card is drawn at random from a deck. What is the probability that it is an ace or a king? |
Algebraic Expression: |
B)
What is the probability that it is either a red card or a black card? |
Algebraic Expression: |
134) Problem #PRAE8R6 "PRAE8R6 - 147494 - The probability t..." |
A)
The probability that you will win a game is 0.45. If you play the game 80 times, how many times would you expect to win? |
Algebraic Expression: |
B)
What are the mean and standard deviation of a binomial distribution with π = 0.45 and N = 80? |
Algebraic Expression: |
135) Problem #PRAE8R7 "PRAE8R7 - 147495 - A fair coin is fl..." |
A fair coin is flipped 9 times. What is the probability of getting exactly 6 heads? |
Algebraic Expression: |
136) Problem #PRAE8R8 "PRAE8R8 - 147496 - When Susan and Je..." |
When Susan and Jessica play a card game, Susan wins 60% of the time. If they play 9 games, what is the probability that Jessica will have won more games than Susan? |
Algebraic Expression: |
137) Problem #PRAE8R9 "PRAE8R9 - 147497 - You flip a coin t..." |
A)
You flip a coin three times. (a) What is the probability of getting heads on only one of your flips? |
Algebraic Expression: |
B)
What is the probability of getting heads on at least one flip? |
Algebraic Expression: |
138) Problem #PRAE8RB "PRAE8RB - 147468 - Q 23/33# 19 Part ..." |
Q 23/33 # 19 Part B Type in a description of your graph. Be sure to include: What number must be on the number line? Open or closed circle? In which direction did you shade? |
Ungraded Open Response: |
139) Problem #PRAE8SC "PRAE8SC - 147500 - A jar contains 10..." |
A)
A jar contains 10 blue marbles, 5 red marbles, 4 green marbles, and 1 yellow marble. Two marbles are chosen (without replacement). What is the probability that one will be green and the other red? |
Algebraic Expression: |
B)
What is the probability that one will be blue and the other yellow? |
Algebraic Expression: |
140) Problem #PRAE8SD "PRAE8SD - 147501 - You roll a fair d..." |
You roll a fair die five times, and you get a 6 each time. What is the probability that you get a 6 on the next roll? |
Algebraic Expression: |
141) Problem #PRAE8SF "PRAE8SF - 147503 - You win a game if..." |
A)
You win a game if you roll a die and get a 2 or a 5. You play this game 60 times. What is the probability that you win between 5 and 10 times (inclusive)? |
Algebraic Expression: |
B)
What is the probability that you will win the game at least 15 times? |
Algebraic Expression: |
C)
What is the probability that you will win the game at least 40 times? |
Algebraic Expression: |
D)
What is the most likely number of wins? |
Algebraic Expression: |
E)
What is the probability of obtaining the number of wins in d? |
Algebraic Expression: |
142) Problem #PRAE8SG "PRAE8SG - 147504 - In a baseball gam..." |
A)
In a baseball game, Tommy gets a hit 30% of the time when facing this pitcher. Joey gets a hit 25% of the time. They are both coming up to bat this inning. What is the probability that Joey or Tommy will get a hit? |
Algebraic Expression: |
B)
What is the probability that neither player gets a hit? |
Algebraic Expression: |
C)
What is the probability that they both get a hit? |
Algebraic Expression: |
143) Problem #PRAE8SH "PRAE8SH - 147505 - An unfair coin ha..." |
An unfair coin has a probability of coming up heads of 0.65. The coin is flipped 50 times. What is the probability it will come up heads 25 or fewer times? (Give answer to at least 3 decimal places). |
Algebraic Expression: |
144) Problem #PRAE8SJ "PRAE8SJ - 147506 - You draw two card..." |
A)
You draw two cards from a deck, what is the probability that both of them are face cards (king, queen, or jack)? |
Algebraic Expression: |
B)
What is the probability that you draw two cards from a deck and both of them are hearts? |
Algebraic Expression: |
145) Problem #PRAE8SK "PRAE8SK - 147507 - True/False: You a..." |
True/False: You are more likely to get a pattern of HTHHHTHTTH than HHHHHHHHTT when you flip a coin 10 times. |
Multiple Choice:
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146) Problem #PRAE8SM "PRAE8SM - 147508 - True/False: Suppo..." |
True/False: Suppose that at your regular physical exam you test positive for a relatively rare disease. You will need to start taking medicine if you have the disease, so you ask your doctor about the accuracy of the test. It turns out that the test is 98% accurate. The probability that you have Disease X is therefore 0.98 and the probability that you do not have it is .02. |
Multiple Choice:
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147) Problem #PRAE6B9 "PRAE6B9 - 145172 - 1. If scores are ..." |
A)
1. If scores are normally distributed with a mean of 35 and a standard deviation of 10, what percent of the scores is: (a) greater than 34? |
Algebraic Expression:
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B)
(b) smaller than 42? |
Algebraic Expression:
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C)
(c) between 28 and 34? |
Algebraic Expression:
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148) Problem #PRAE6XH "PRAE6XH - 145738 - 2. (a) What are t..." |
A)
2. (a) What are the mean and standard deviation of the standard normal distribution? insert answer as mean:____, sd:____ |
Algebraic Expression:
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B)
(b) What would be the mean and standard deviation of a distribution created by multiplying the standard normal distribution by 6 and adding 75? |
Algebraic Expression:
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149) Problem #PRAE6XK "PRAE6XK - 145740 - 3. The normal dis..." |
3. The normal distribution is defined by two parameters. What are they? |
Ungraded Open Response: |
150) Problem #PRAE6XM "PRAE6XM - 145741 - 4. What proportio..." |
A)
4. What proportion of a normal distribution is within one standard deviation of the mean? |
Algebraic Expression:
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B)
(b) What proportion is more than 2.0 standard deviations from the mean? |
Algebraic Expression:
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C)
(c) What proportion is between 1.25 and 2.1 standard deviations above the mean? |
Algebraic Expression:
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151) Problem #PRAE6XN "PRAE6XN - 145742 - 5. A test is norm..." |
A)
5. A test is normally distributed with a mean of 70 and a standard deviation of 8. (a) What score would be needed to be in the 85th percentile? |
Algebraic Expression:
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B)
(b) What score would be needed to be in the 22nd percentile? |
Algebraic Expression:
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152) Problem #PRAE6XQ "PRAE6XQ - 145744 - 6. Assume a norma..." |
6. Assume a normal distribution with a mean of 70 and a standard deviation of 12. What limits would include the middle 65% of the cases? |
Algebraic Expression:
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153) Problem #PRAE6XS "PRAE6XS - 145746 - 7. A normal distr..." |
A)
7. A normal distribution has a mean of 20 and a standard deviation of 4. Find the Z scores for the following numbers: (a) 28 |
Algebraic Expression:
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B)
(b) 18 |
Algebraic Expression:
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C)
(c) 10 |
Algebraic Expression:
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D)
(d) 23 |
Algebraic Expression:
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154) Problem #PRAE6XT "PRAE6XT - 145747 - 8. Assume the spe..." |
A)
8. Assume the speed of vehicles along a stretch of I-10 has an approximately normal distribution with a mean of 71 mph and a standstard deviation of 8 mph. (a) The current speed limit is 65 mph. What is the proportion of vehicles less than or equal to the speed limit? |
Algebraic Expression:
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B)
(b) What proportion of the vehicles would be going less than 50 mph? |
Algebraic Expression:
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C)
(c) A new speed limit will be initiated such that approximately 10% of vehicles will be over the speed limit. What is the new speed limit based on this criterion? |
Algebraic Expression:
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D)
(d) In what way do you think the actual distribution of speeds differs from a normal distribution? |
Ungraded Open Response: |
155) Problem #PRAE6XV "PRAE6XV - 145749 - 9. A variable is ..." |
9. A variable is normally distributed with a mean of 120 and a standard deviation of 5. One score is randomly sampled. What is the probability it is above 127? |
Algebraic Expression:
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156) Problem #PRAE6XW "PRAE6XW - 145750 - 10. You want to u..." |
10. You want to use the normal distribution to approximate the binomial distribution. Explain what you need to do to find the probability of obtaining exactly 7 heads out of 12 flips. |
Ungraded Open Response: |
157) Problem #PRAE6XX "PRAE6XX - 145751 - 11. A group of st..." |
A)
11. A group of students at a school takes a history test. The distribution is normal with a mean of 25, and a standard deviation of 4. (a) Everyone who scores in the top 30% of the distribution gets a certificate. What is the lowest score someone can get and still earn a certificate? |
Algebraic Expression:
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B)
(b) The top 5% of the scores get to complete in a statewide history contest. What is the lowest score someone can get and still go onto complete with the rest of the state? |
Algebraic Expression:
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158) Problem #PRAE6X3 "PRAE6X3 - 145755 - 12. Use the norma..." |
12. Use the normal distribution to approximate the binomial distribution and find the probability of getting 15 to 18 heads out of 25 flips. Compare this to what you get when you calculate the probability using the binomial distribution.Write your answers out to four decimal places. |
Algebraic Expression:
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159) Problem #PRAE6X7 "PRAE6X7 - 145759 - 13. True/False: F..." |
13. True/False: For any normal distribution, the mean, median, and mode will have the same value. |
Multiple Choice:
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160) Problem #PRAE6X8 "PRAE6X8 - 145760 - 14. True/false: I..." |
14. True/false: In a normal distribution, 11.5% of scores are greater than Z=1.2. |
Multiple Choice:
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161) Problem #PRAE6YA "PRAE6YA - 145762 - 15. True/false: T..." |
15. True/false: The percentile rank for the mean is 50% for any normal distribution. |
Multiple Choice:
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162) Problem #PRAE6YF "PRAE6YF - 145767 - 16. True/false: T..." |
16. True/false: The larger the n, the better the normal distribution approximates the binomial distribution. |
Multiple Choice:
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163) Problem #PRAE6YG "PRAE6YG - 145768 - 17. True/false: A..." |
17. True/false: A Z-score represents the number of standard deviations above or below the mean. |
Multiple Choice:
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164) Problem #PRAE6YH "PRAE6YH - 145769 - 18. True/false: A..." |
18. True/false: Abraham de Moivre, a consultant to gamblers, discovered the normal distribution when trying to approximate the binomial distribution to make his computations easier. |
Multiple Choice:
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165) Problem #PRAE6YK "PRAE6YK - 145771 - 19. True/false: T..." |
19. True/false: The standard deviation of the blue distribution shown below is about 10. |
Multiple Choice:
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166) Problem #PRAE6YM "PRAE6YM - 145772 - 20. True/false: I..." |
20. True/false: In the figure below, the red distribution has a larger standard deviation than the blue distribution. |
Multiple Choice:
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167) Problem #PRAE6YP "PRAE6YP - 145774 - 21. True/false: T..." |
21. True/false: The red distribution has more area underneath the curve than the blue distribution does. |
Multiple Choice:
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168) Problem #PRAE3SN "PRAE3SN - OSB-CH7 #1" |
Algebraic Expression: |
169) Problem #PRAEUYT "PRAEUYT - OSB-CH7 #2" |
A)
A population has a mean of 50 and a standard deviation of 6. What are the mean and standard deviation of the sampling distribution of the mean for N = 16? |
Algebraic Expression: |
B)
A population has a mean of 50 and a standard deviation of 6. What are the mean and standard deviation of the sampling distribution of the mean for N = 20? |
Algebraic Expression: |
C)
Given a test that is normally distributed with a mean of 100 and a standard deviation of 12, find the probability that a single score drawn at random will be greater than 110 |
Algebraic Expression: |
D)
Given a test that is normally distributed with a mean of 100 and a standard deviation of 12 find the probability that a sample of 25 scores will have a mean greater than 105 |
Algebraic Expression: |
E)
Given a test that is normally distributed with a mean of 100 and a standard deviation of 12 find the probability that a sample of 64 scores will have a mean greater than 105 |
Algebraic Expression: |
F)
Given a test that is normally distributed with a mean of 100 and a standard deviation of 12, find the probability that the mean of a sample of 16 scores will be either less than 95 or greater than 105 |
Algebraic Expression: |
170) Problem #PRAE3RF "PRAE3RF - OSB-CH7 #3" |
What term refers to the standard deviation of the sampling distribution? |
Algebraic Expression: |
171) Problem #PRAE3RJ "PRAE3RJ - OSB-CH7 #4" |
If the standard error of the mean is 10 for N = 12, what is the standard error of the mean for N = 22? (b) If the standard error of the mean is 50 for N = 25, what is it for N = 64? |
Algebraic Expression: |
172) Problem #PRAE3RM "PRAE3RM - OSB-CH7 #5" |
A questionnaire is developed to assess women's and men's attitudes toward using animals in research. One question asks whether animal research is wrong and is answered on a 7-point scale. Assume that in the population, the mean for women is 5, the mean for men is 4, and the standard deviation for both groups is 1.5. Assume the scores are normally distributed. If 12 women and 12 men are selected randomly, what is the probability that the mean of the women will be more than 1.5 points higher than the mean of the men? |
Algebraic Expression: |
173) Problem #PRAE3RT "PRAE3RT - OSB-CH 7 #6" |
If the correlation between reading achievement and math achievement in the population of fifth graders were 0.60, what would be the probability that in a sample of 28 students, the sample correlation coefficient would be greater than 0.65? |
Algebraic Expression: |
174) Problem #PRAE3RX "PRAE3RX - 142682 - OSB- CH 7 #7" |
If numerous samples of N = 15 are taken from a uniform distribution and a relative frequency distribution of the means is drawn, what would be the shape of the frequency distribution? |
Algebraic Expression: |
175) Problem #PRAE3SF "PRAE3SF - OSB-CH7 #8" |
A normal distribution has a mean of 20 and a standard deviation of 10. Two scores are sampled randomly from the distribution and the second score is subtracted from the first. What is the probability that the difference score will be greater than 5? |
Algebraic Expression: |
176) Problem #PRAE3SQ "PRAE3SQ - OSB-CH7 #9" |
Algebraic Expression: |
177) Problem #PRAE3SS "PRAE3SS - OSB-CH7 #10" |
Algebraic Expression: |
178) Problem #PRAE3SU "PRAE3SU - OSB-CH7 #11" |
Algebraic Expression: |
179) Problem #PRAE3SW "PRAE3SW - OSB-CH7 #12" |
A)
The correlation between self esteem and extraversion is .30. A sample of 84 is taken. What is the probability that the correlation will be less than 0.10? |
Algebraic Expression: |
B)
Refer to part one. What is the probability that the correlation will be greater than 0.25? |
Algebraic Expression: |
180) Problem #PRAE4FA "PRAE4FA - OSB-CH7 #14" |
A)
In a city, 70% of the people prefer Candidate A. Suppose 30 people from this city were sampled. What is the mean of the sampling distribution of p? |
Algebraic Expression: |
B)
What is the standard error of p? |
Algebraic Expression: |
C)
What is the probability that 80% or more of this sample will prefer Candidate A? |
Algebraic Expression: |
D)
What is the probability that 45% or more of this sample will prefer some other candidate? |
Algebraic Expression: |
181) Problem #PRAE4FF "PRAE4FF - OSB-CH7 #16" |
In the population, the mean SAT score is 1000. Would you be more likely (or equally likely) to get a sample mean of 1200 if you randomly sampled 10 students or if you randomly sampled 30 students? Explain |
Algebraic Expression: |
182) Problem #PRAE4FH "PRAE4FH - OSB-CH7 #17" |
True or False. The standard error of the mean is smaller when N = 20 than when N = 10. |
Algebraic Expression: |
183) Problem #PRAE4FN "PRAE4FN - OSB-CH7 #18" |
True or false. The sampling distribution of r = .8 becomes normal as N increases. |
Algebraic Expression: |
184) Problem #PRAE4FQ "PRAE4FQ - OSB-CH7 #19" |
Algebraic Expression: |
185) Problem #PRAE4FS "PRAE4FS - OSB-CH7 #20" |
True or false. In your school, 40% of students watch TV at night. You randomly ask 5 students every day if they watch TV at night. Every day, you would find that 2 of the 5 do watch TV at night. |
Algebraic Expression: |
186) Problem #PRAE4FV "PRAE4FV - 143362 - OSB-CH7 #21" |
True or false: The median has a sampling distribution |
Algebraic Expression: |
187) Problem #PRAE8DE "PRAE8DE - 147130 - When would the me..." |
A)
When would the mean grade in a class on a final exam be considered a statistic? |
Ungraded Open Response: |
B)
When would it be considered a parameter? |
Ungraded Open Response: |
188) Problem #PRAE8DM "PRAE8DM - 147136 - Define bias in te..." |
Define bias in terms of expected value. |
Ungraded Open Response: |
189) Problem #PRAE8DN "PRAE8DN - 147137 - Is it possible fo..." |
A)
Is it possible for a statistic to be unbiased yet very imprecise? |
Ungraded Open Response: |
B)
How about being very accurate but biased? |
Ungraded Open Response: |
190) Problem #PRAE8DP "PRAE8DP - 147138 - Why is a 99% conf..." |
Why is a 99% confidence interval wider than a 95% confidence interval? |
Ungraded Open Response: |
191) Problem #PRAE8DQ "PRAE8DQ - 147139 - When you construc..." |
When you construct a 95% confidence interval, what are you 95% confident about? |
Ungraded Open Response: |
192) Problem #PRAE8DR "PRAE8DR - 147140 - What is the diffe..." |
What is the difference in the computation of a confidence interval between cases in which you know the population standard deviation and cases in which you have to estimate it? |
Ungraded Open Response: |
193) Problem #PRAE8DT "PRAE8DT - 147142 - Assume a research..." |
Assume a researcher found that the correlation between a test he or she developed and job performance was 0.55 in a study of 28 employees. If correlations under .35 are considered unacceptable, would you have any reservations about using this test to screen job applicants? |
Algebraic Expression: |
194) Problem #PRAE8DU "PRAE8DU - 147143 - What is the effec..." |
What is the effect of sample size on the width of a confidence interval? |
Ungraded Open Response: |
195) Problem #PRAE8DV "PRAE8DV - 147144 - How does the t di..." |
A)
How does the t distribution compare with the normal distribution? |
Ungraded Open Response: |
B)
How does this difference affect the size of confidence intervals constructed using z relative to those constructed using t? |
Ungraded Open Response: |
C)
Does sample size make a difference? |
Ungraded Open Response: |
196) Problem #PRAE8DW "PRAE8DW - 147145 - The effectiveness..." |
The effectiveness of a blood-pressure drug is being investigated. How might an experimenter demonstrate that, on average, the reduction in systolic blood pressure is 20 or more? |
Ungraded Open Response: |
197) Problem #PRAE8DX "PRAE8DX - 147146 - A population is k..." |
A)
A population is known to be normally distributed with a standard deviation of 2.8. (a) Compute the 95% confidence interval on the mean based on the following sample of nine: 8, 9, 10, 13, 14, 16, 17, 20, 21 Round to the nearest hundreth. |
Algebraic Expression:
|
B)
Now compute the 99% confidence interval using the same data. |
Algebraic Expression:
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198) Problem #PRAE8DZ "PRAE8DZ - 147148 - A person claims t..." |
A)
A person claims to be able to predict the outcome of flipping a coin. This person is correct 16/25 times. Compute the 95% confidence interval on the proportion of times this person can predict coin flips correctly. |
Algebraic Expression:
|
B)
What conclusion can you draw about this test of his ability to predict the future? |
Ungraded Open Response: |
199) Problem #PRAE8D2 "PRAE8D2 - 147149 - What does it mean..." |
What does it mean that the variance (computed by dividing by N) is a biased statistic? |
Ungraded Open Response: |
200) Problem #PRAE8D3 "PRAE8D3 - 147150 - A confidence inte..." |
A confidence interval for the population mean computed from an N of 16 ranges from 12 to 28. A new sample of 36 observations is going to be taken. You can't know in advance exactly what the confidence interval will be because it depends on the random sample. Even so, you should have some idea of what it will be. Give your best estimation. |
Ungraded Open Response: |
201) Problem #PRAE8D4 "PRAE8D4 - 147151 - You take a sample..." |
A)
You take a sample of 22 from a population of test scores, and the mean of your sample is 60. You know the standard deviation of the population is 10. What is the 99% confidence interval on the population mean. |
Ungraded Open Response: |
B)
Now assume that you do not know the population standard deviation, but the standard deviation in your sample is 10. What is the 99% confidence interval on the mean now? |
Algebraic Expression: |
202) Problem #PRAE8D6 "PRAE8D6 - 147153 - You read about a ..." |
You read about a survey in a newspaper and find that 70% of the 250 people sampled prefer Candidate A. You are surprised by this survey because you thought that more like 50% of the population preferred this candidate. Based on this sample, is 50% a possible population proportion? Compute the 95% confidence interval to be sure. |
Algebraic Expression: |
203) Problem #PRAE8D7 "PRAE8D7 - 147154 - Heights for teena..." |
A)
Heights for teenage boys and girls were calculated. The mean height for the sample of 12 boys was 174 cm and the variance was 62. For the sample of 12 girls, the mean was 166 cm and the variance was 65.What is the 95% confidence interval on the difference between population means? |
Algebraic Expression: |
B)
What is the 99% confidence interval on the difference between population means? |
Algebraic Expression: |
C)
Do you think the mean difference in the population could be about 5? Why or why not? |
Ungraded Open Response: |
204) Problem #PRAE8D8 "PRAE8D8 - 147155 - You were interest..." |
A)
You were interested in how long the average psychology major at your college studies per night, so you asked 10 psychology majors to tell you the amount they study. They told you the following times: 2, 1.5, 3, 2, 3.5, 1, 0.5, 3, 2, 4. Find the 95% confidence interval on the population mean. |
Algebraic Expression: |
B)
Find the 90% confidence interval on the population mean. |
Algebraic Expression: |
205) Problem #PRAE57Z "PRAE57Z - 145040 - An experiment is ..." |
An experiment is conducted to test the claim that James Bond can taste the difference between a Martini that is shaken and one that is stirred. What is the null hypothesis? |
Algebraic Expression: |
206) Problem #PRAE573 "PRAE573 - 145042 - The following exp..." |
The following explanation is incorrect. What three words should be added to make it correct? The probability value is the probability of obtaining a statistic as different from the parameter specified in the null hypothesis as the statistic obtained in the experiment. The probability value is computed assuming that the null hypothesis is true. |
Algebraic Expression: |
207) Problem #PRAE575 "PRAE575 - 145044 - Why do experiment..." |
Why do experimenters test hypotheses they think are false? |
Algebraic Expression: |
208) Problem #PRAE576 "PRAE576 - 145045 - State the null hy..." |
A)
State the null hypothesis for an experiment testing whether echinacea decreases the length of colds. |
Algebraic Expression: |
B)
State the null hypothesis for a correlational study on the relationship between brain size and intelligence. |
Algebraic Expression: |
C)
State the null hypothesis for an investigation of whether a self-proclaimed psychic can predict the outcome of a coin flip. |
Algebraic Expression: |
D)
State the null hypothesis for a study comparing a drug with a placebo on the amount of pain relief. (A one-tailed test was used.) |
Algebraic Expression: |
209) Problem #PRAE58G "PRAE58G - 145055 - Assume the null h..." |
Assume the null hypothesis is that µ = 50 and that the graph shown below is the sampling distribution of the mean (M). Would a sample value of M= 60 be significant in a two-tailed test at the .05 level? Roughly what value of M would be needed to be significant? |
Algebraic Expression: |
210) Problem #PRAE58J "PRAE58J - 145057 - A researcher deve..." |
A researcher develops a new theory that predicts that vegetarians will have more of a particular vitamin in their blood than non-vegetarians. An experiment is conducted and vegetarians do have more of the vitamin, but the difference is not significant. The probability value is 0.13. Should the experimenter's confidence in the theory increase, decrease, or stay the same? |
Algebraic Expression: |
211) Problem #PRAE58Q "PRAE58Q - 145062 - A researcher hypo..." |
A researcher hypothesizes that the lowering in cholesterol associated with weight loss is really due to exercise. To test this, the researcher carefully controls for exercise while comparing the cholesterol levels of a group of subjects who lose weight by dieting with a control group that does not diet. The difference between groups in cholesterol is not significant. Can the researcher claim that weight loss has no effect? |
Algebraic Expression: |
212) Problem #PRAE58W "PRAE58W - 145068 - A significance te..." |
A significance test is performed and p = .20. Why can't the experimenter claim that the probability that the null hypothesis is true is .20? |
Algebraic Expression: |
213) Problem #PRAE58X "PRAE58X - 145069 - For a drug to be ..." |
For a drug to be approved by the FDA, the drug must be shown to be safe and effective. If the drug is significantly more effective than a placebo, then the drug is deemed effective. What do you know about the effectiveness of a drug once it has been approved by the FDA (assuming that there has not been a Type I error)? |
Algebraic Expression: |
214) Problem #PRAE583 "PRAE583 - 145073 - When is it valid ..." |
When is it valid to use a one-tailed test? What is the advantage of a one-tailed test? Give an example of a null hypothesis that would be tested by a one-tailed test. |
Algebraic Expression: |
215) Problem #PRAE584 "PRAE584 - 145074 - Distinguish betwe..." |
Distinguish between probability value and significance level. |
Algebraic Expression: |
216) Problem #PRAE585 "PRAE585 - 145075 - Suppose a study w..." |
Suppose a study was conducted on the effectiveness of a class on "How to take tests." The SAT scores of an experimental group and a control group were compared. (There were 100 subjects in each group.) The mean score of the experimental group was 503 and the mean score of the control group was 499. The difference between means was found to be significant, p = .037. What do you conclude about the effectiveness of the class? |
Algebraic Expression: |
217) Problem #PRAE587 "PRAE587 - 145077 - Is it more conser..." |
Is it more conservative to use an alpha level of .01 or an alpha level of .05? Would beta be higher for an alpha of .05 or for an alpha of .01? |
Algebraic Expression: |
218) Problem #PRAE588 "PRAE588 - 145078 - Why is "Ho: "M1 =..." |
Why is "Ho: "M1 = M2" not a proper null hypothesis? |
Algebraic Expression: |
219) Problem #PRAE589 "PRAE589 - 145079 - An experimenter e..." |
An experimenter expects an effect to come out in a certain direction. Is this sufficient basis for using a one-tailed test? Why or why not? |
Algebraic Expression: |
220) Problem #PRAE59A "PRAE59A - 145080 - An experimenter e..." |
An experimenter expects an effect to come out in a certain direction. Is this sufficient basis for using a one-tailed test? Why or why not? |
Algebraic Expression: |
221) Problem #PRAE59B "PRAE59B - 145081 - A two-tailed prob..." |
A two-tailed probability is .03. What is the one-tailed probability if the effect were in the specified direction? What would it be if the effect were in the other direction? |
Algebraic Expression: |
222) Problem #PRAE59C "PRAE59C - 145082 - You choose an alp..." |
You choose an alpha level of .01 and then analyze your data. (a) What is the probability that you will make a Type I error given that the null hypothesis is true? (b) What is the probability that you will make a Type I error given that the null hypothesis is false? |
Algebraic Expression: |
223) Problem #PRAE59D "PRAE59D - 145083 - You are playing a..." |
You are playing a game at a carnival. You have to draw one of four cards, and the person running the game claims you have a 1/4 chance of winning. You think that people win the the game less often that this, so you decide to test your hypothesis. You watch many people play the game, and you only see 2 people out of 20 win. (a) Assuming that the probability of winning really is .25, what is the probability of this few people or fewer winning? (b) Can you reject the null hypothesis at the .05 level? |
Algebraic Expression: |
224) Problem #PRAE59E "PRAE59E - 145084 - You believe that ..." |
You believe that a coin a magician uses is biased, but you are not sure if it will come up heads or tails more often. You watch the magician flip the coin and record what percentage of the time the coin comes up heads. (a) Is this a one-tailed or two-tailed test? (b) Assuming that the coin is fair, what is the probability that out of 30 flips, it would come up one side 23 or more times? (c) Can you reject the null hypothesis at the .05 level? What about at the .01 level? |
Algebraic Expression: |
225) Problem #PRAE59G "PRAE59G - 145086 - Why doesn't it ma..." |
Why doesn't it make sense to test the hypothesis that the sample mean is 42? |
Algebraic Expression: |
226) Problem #PRAE59J "PRAE59J - 145088 - It is easier to r..." |
It is easier to reject the null hypothesis if the researcher uses a smaller alpha (α) level. |
Multiple Choice:
|
227) Problem #PRAE59M "PRAE59M - 145090 - You are more like..." |
You are more likely to make a Type I error when using a small sample than when using a large sample. |
Multiple Choice:
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228) Problem #PRAE59N "PRAE59N - 145091 - You accept the al..." |
You accept the alternative hypothesis when you reject the null hypothesis. |
Multiple Choice:
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229) Problem #PRAE59P "PRAE59P - 145092 - You do not accept..." |
You do not accept the null hypothesis when you fail to reject it. |
Multiple Choice:
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230) Problem #PRAE59Q "PRAE59Q - 145093 - A researcher risk..." |
A researcher risks making a Type I error any time the null hypothesis is rejected. |
Multiple Choice:
|
231) Problem #PRAE8EF "PRAE8EF - 147162 - The scores of a r..." |
A)
The scores of a random sample of 8 students on a physics test are as follows: 60, 62, 67, 69, 70, 72, 75, and 78. Test to see if the sample mean is significantly different from 65 at the .05 level. Report the t and p values. |
Algebraic Expression: |
B)
The researcher realizes that she accidentally recorded the score that should have been 76 as 67. Are these corrected scores significantly different from 65 at the .05 level? |
Algebraic Expression: |
232) Problem #PRAE8EG "PRAE8EG - 147163 - A (hypothetical) ..." |
A (hypothetical) experiment is conducted on the effect of alcohol on perceptual motor ability. Ten subjects are each tested twice, once after having two drinks and once after having two glasses of water. The two tests were on two different days to give the alcohol a chance to wear off. Half of the subjects were given alcohol first and half were given water first. The scores of the 10 subjects are shown below. The first number for each subject is their performance in the "water" condition. Higher scores reflect better performance. Test to see if alcohol had a significant effect. Report the t and p values.
|
Algebraic Expression: |
233) Problem #PRAE8EH "PRAE8EH - 147164 - The scores on a (..." |
A)
The scores on a (hypothetical) vocabulary test of a group of 20 year olds and a group of 60 year olds are shown below.
|
Algebraic Expression: |
B)
List the assumptions made in computing your answer. |
Algebraic Expression: |
234) Problem #PRAE8EJ "PRAE8EJ - 147165 - The sampling dist..." |
The sampling distribution of a statistic is normally distributed with an estimated standard error of 12 (df = 20). (a) What is the probability that you would have gotten a mean of 107 (or more extreme) if the population parameter were 100? Is this probability significant at the .05 level (two-tailed)? (b) What is the probability that you would have gotten a mean of 95 or less (one-tailed)? Is this probability significant at the .05 level? |
Algebraic Expression: |
235) Problem #PRAE8EK "PRAE8EK - 147166 - How do you decide..." |
How do you decide whether to use an independent groups t test or a correlated t test (test of dependent means)? |
Algebraic Expression: |
236) Problem #PRAE8EM "PRAE8EM - 147167 - An experiment com..." |
A)
An experiment compared the ability of three groups of subjects to remember briefly-presented chess positions. The data are shown below.
|
Algebraic Expression: |
B)
Now compare each pair of groups using t-tests. Make sure to control for the familywise error rate (at 0.05) by using the Bonferroni correction. Specify the alpha level you used. |
Algebraic Expression: |
237) Problem #PRAE8EN "PRAE8EN - 147168 - Below are data sh..." |
A)
Below are data showing the results of six subjects on a memory test. The three scores per subject are their scores on three trials (a, b, and c) of a memory task. Are the subjects getting better each trial? Test the linear effect of trial for the data.
|
Algebraic Expression: |
B)
Compute a one-sample t-test on this column (with the L values for each subject) you created. |
Algebraic Expression: |
238) Problem #PRAE8EP "PRAE8EP - 147169 - Participants thre..." |
A)
Participants threw darts at a target. In one condition, they used their preferred hand; in the other condition, they used their other hand. All subjects performed in both conditions (the order of conditions was counterbalanced). Their scores are shown below.
|
Algebraic Expression: |
B)
Calculate the two-tailed t and p values using this t test. |
Algebraic Expression: |
C)
Calculate the one-tailed t and p values using this t test. |
Algebraic Expression: |
239) Problem #PRAE8EQ "PRAE8EQ - 147170 - Assume the data i..." |
Assume the data in the previous problem were collected using two different groups of subjects: One group used their preferred hand and the other group used their non-preferred hand. Analyze the data and compare the results to those for the previous problem. |
Algebraic Expression: |
240) Problem #PRAE8ER "PRAE8ER - 147171 - You have 4 means,..." |
A)
You have 4 means, and you want to compare each mean to every other mean. How many tests total are you going to compute? |
Algebraic Expression: |
B)
What would be the chance of making at least one Type I error if the Type I error for each test was .05 and the tests were independent? |
Algebraic Expression: |
C)
Are the tests independent and how does independence/non-independence affect the probability in the previous problem. |
Algebraic Expression: |
241) Problem #PRAE8ES "PRAE8ES - 147172 - In an experiment,..." |
A)
In an experiment, participants were divided into 4 groups. There were 20 participants in each group, so the degrees of freedom (error) for this study was 80 - 4 = 76. Tukey's HSD test was performed on the data. Calculate the p value for each pair based on the Q value given below.
|
Algebraic Expression: |
B)
Which differences are significant at the .05 level? |
Algebraic Expression: |
242) Problem #PRAE8ET "PRAE8ET - 147173 - If you have 5 gro..." |
If you have 5 groups in your study, why shouldn't you just compute a t test of each group mean with each other group mean? |
Algebraic Expression: |
243) Problem #PRAE8EU "PRAE8EU - 147174 - You are conductin..." |
A)
You are conducting a study to see if students do better when they study all at once or in intervals. One group of 12 participants took a test after studying for one hour continuously. The other group of 12 participants took a test after studying for three twenty minute sessions. The first group had a mean score of 75 and a variance of 120. The second group had a mean score of 86 and a variance of 100. What is the calculated t value? Are the mean test scores of these two groups significantly different at the .05 level? |
Algebraic Expression: |
B)
What would the t value be if there were only 6 participants in each group? Would the scores be significant at the .05 level? |
Algebraic Expression: |
244) Problem #PRAE8EV "PRAE8EV - 147175 - A new test was de..." |
A new test was designed to have a mean of 80 and a standard deviation of 10. A random sample of 20 students at your school take the test, and the mean score turns out to be 85. Does this score differ significantly from 80? |
Algebraic Expression: |
245) Problem #PRAE8EW "PRAE8EW - 147176 - You perform a one..." |
You perform a one-sample t test and calculate a t statistic of 3.0. The mean of your sample was 1.3 and the standard deviation was 2.6. How many participants were used in this study? |
Algebraic Expression: |
246) Problem #PRAE8EX "PRAE8EX - 147177 - Suppose a variabl..." |
A)
Suppose a variable X can take the values 1, 2, 3, or 4. The probabilites associated with each outcome are 1=.1, 2=.3, 3=.4, and 4=.2. What is probability that X is equal to 2 or 3? |
Exact Match (case sensitive):
|
B)
What is the probability that X is greater than 1? |
Exact Match (case sensitive):
|
C)
What is the probability that X is less than or equal to 3? |
Algebraic Expression:
|
D)
What is the probability X is less than or equal to 1? |
Exact Match (case sensitive):
|
E)
What is the probability that X is less than or equal to 2? |
Exact Match (case sensitive):
|
247) Problem #PRAE8EY "PRAE8EY - 147178 - True/false: The c..." |
True/false: The contrasts (-3, 1 1 1) and (0, 0 , -1, 1) are orthogonal. |
Algebraic Expression: |
248) Problem #PRAE8EZ "PRAE8EZ - 147179 - True/false: If yo..." |
True/false: If you are making 4 comparisons between means, then based on the Bonferroni correction, you should use an alpha level of .01 for each test. |
Algebraic Expression: |
249) Problem #PRAE8E2 "PRAE8E2 - 147180 - True/false: Corre..." |
True/false: Correlated t tests almost always have greater power than independent t tests. |
Algebraic Expression: |
250) Problem #PRAE8E3 "PRAE8E3 - 147181 - True/false:The gr..." |
True/false:The graph below represents a violation of the homogeneity of variance assumption. |
Algebraic Expression: |
251) Problem #PRAE675 "PRAE675 - 146005 - #1 Power" |
Define power in your own words. |
Ungraded Open Response: |
252) Problem #PRAE677 "PRAE677 - 146007 - #2 Power" |
List 3 measures one can take to increase the power of an experiment. Explain why your measures result in greater power. |
Ungraded Open Response: |
253) Problem #PRAE678 "PRAE678 - #3 Power" |
Population 1 mean = 36 Population 2 mean = 45 Both population variances are 10. What is the probability that a t test will find a significant difference between means at the 0.05 level? Give results for both one- and two-tailed tests. Hint: the power of a one-tailed test at 0.05 level is the power of a two-tailed test at 0.10. |
Ungraded Open Response: |
254) Problem #PRAE679 "PRAE679 - #4 Power" |
Rank order the following in terms of power.
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Algebraic Expression: |
255) Problem #PRAE68A "PRAE68A - 146010 - #5 Power (a, b, and c)" |
A)
Alan, while snooping around his grandmother's basement stumbled upon a shiny object protruding from under a stack of boxes . When he reached for the object a genie miraculously materialized and stated: "You have found my magic coin. If you flip this coin an infinite number of times you will notice that heads will show 60% of the time." Soon after the genie's declaration he vanished, never to be seen again. Alan, excited about his new magical discovery, approached his friend Ken and told him about what he had found. Ken was skeptical of his friend's story, however, he told Alan to flip the coin 100 times and to record how many flips resulted with heads. What is Ken's null hypothesis? |
Ungraded Open Response: |
B)
What is the probability that Alan will be able convince Ken that his coin has special powers by finding a p value below 0.05 (one tailed). Use the Binomial Calculator (and some trial and error). |
Algebraic Expression: |
C)
If Ken told Alan to flip the coin only 20 times, what is the probability that Alan will not be able to convince Ken (by failing to reject the null hypothesis at the 0.05 level)? |
Algebraic Expression: |
256) Problem #PRAE797 "PRAE797 - 147030 - What is th..." |
A)
What is the equation for a regression line? |
Multiple Choice:
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B)
What does each term in the line refer to? |
Ungraded Open Response:
|
257) Problem #PRAE8AA "PRAE8AA - 147033 - The formul..." |
A)
The formula for a regression equation is Y' = 2X + 9. (a) What would be the predicted score for a person scoring 6 on X? |
Algebraic Expression:
|
B)
(b) If someone's predicted score was 14, what was this person's score on X? |
Algebraic Expression:
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258) Problem #PRAE8FK "PRAE8FK - 147197 - What criterion is..." |
What criterion is used for deciding which regression line fits best? |
Ungraded Open Response:
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259) Problem #PRAE8FM "PRAE8FM - 147198 - What does the sta..." |
A)
What does the standard error of the estimate measure? |
Ungraded Open Response:
|
B)
What is the formula for the standard error of the estimate? |
Multiple Choice:
|
260) Problem #PRAE8FP "PRAE8FP - 147200 - (a) In a regressi..." |
A)
(a) In a regression analysis, the sum of squares for the predicted scores is 100 and the sum of squares error is 200, what is R2? |
Algebraic Expression:
|
B)
(b) In a different regression analysis, 40% of the variance was explained. The sum of squares total is 1000. What is the sum of squares of the predicted values? |
Ungraded Open Response: |
261) Problem #PRAE8K2 "PRAE8K2 - 147335 - What assum..." |
What assumptions are needed to calculate the various inferential statistics of linear regression? |
Ungraded Open Response:
|
262) Problem #PRAE8K5 "PRAE8K5 - 147338 - A sample o..." |
A sample of X and Y scores is taken, and a regression line is used to predict Y from X. If SSY' = 300, SSE = 500, and N = 50, what is: (relevant section relevant section) (a) SSY? (b) the standard error of the estimate? (c) R2? |
Ungraded Open Response: |
263) Problem #PRAE8K7 "PRAE8K7 - 147340 - Using line..." |
Using linear regression, find the predicted post-test score for someone with a score of 43 on the pre-test. (relevant section)
|
Ungraded Open Response: |
264) Problem #PRAE8K8 "PRAE8K8 - 147341 - The equati..." |
The equation for a regression line predicting the number of hours of TV watched by children (Y) from the number of hours of TV watched by their parents (X) is Y' = 4 + 1.2X. (a) If the standard error of b is .4, is the slope statistically significant at the .05 level? (relevant section) (b) If the mean of X is 8, what is the mean of Y? |
Ungraded Open Response: |
265) Problem #PRAE8FW "PRAE8FW - 147207 - Based on the tabl..." |
Based on the table below, compute the regression line that predicts Y from X. |
Multiple Choice:
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266) Problem #PRAE8FV "PRAE8FV - 147206 - . Does A o..." |
. Does A or B have a larger standard error of the estimate?(couldnt insert picture) |
Algebraic Expression:
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267) Problem #PRAE8FU "PRAE8FU - 147205 - True/false: If th..." |
True/false: If the slope of a simple linear regression line is statistically significant, then the correlation will also always be significant. |
Algebraic Expression:
|
268) Problem #PRAE8FT "PRAE8FT - 147204 - True/false: If th..." |
A)
True/false: If the slope of the relationship between X an Y is larger for Population 1 than for Population 2, the correlation will necessarily be larger in Population 1 than in Population 2. |
Exact Match (case sensitive):
|
B)
Why or Why not ? |
Ungraded Open Response: |
269) Problem #PRAE8FS "PRAE8FS - 147203 - True/false: If th..." |
True/false: If the correlation is .8, then 40% of the variance is explained. |
Algebraic Expression:
|
270) Problem #PRAE8FR "PRAE8FR - 147202 - True/false: If th..." |
True/false: If the actual Y score was 31, but the predicted score was 28, then the error of prediction is 3 |
Algebraic Expression:
|
271) Problem #PRAE6N4 "PRAE6N4 - 145477 - Which of the two ..." |
Which of the two Chi Square distributions shown below (A or B) has the larger degrees of freedom? How do you know? |
Algebraic Expression: |
272) Problem #PRAE6N5 "PRAE6N5 - 145478 - Twelve subjects w..." |
Twelve subjects were each given two flavors of ice cream to taste and then were asked whether they liked them. Two of the subjects liked the first flavor and nine of them liked the second flavor. Is it valid to use the Chi Square test to determine whether this difference in proportions is significant? Why or why not? |
Algebraic Expression: |
273) Problem #PRAE6N6 "PRAE6N6 - 145479 - A die is suspecte..." |
A die is suspected of being biased. It is rolled 25 times with the following result:
Conduct a significance test to see if the die is biased. (a) What Chi Square value do you get and how many degrees of freedom does it have? (b) What is the p value? |
Algebraic Expression: |
274) Problem #PRAE6N7 "PRAE6N7 - 145480 - A recent experime..." |
A recent experiment investigated the relationship between smoking and urinary incontinence. Of the 322 subjects in the study who were incontinent, 113 were smokers, 51 were former smokers, and 158 had never smoked. Of the 284 control subjects who were not incontinent, 68 were smokers, 23 were former smokers, and 193 had never smoked. (a) Create a table displaying this data. (b) What is the expected frequency in each cell? (c) Conduct a significance test to see if there is a relationship between smoking and incontinence. What Chi Square value do you get? What p value do you get? (d) What do you conclude? |
Algebraic Expression: |
275) Problem #PRAE6N8 "PRAE6N8 - 145481 - At a school pep r..." |
At a school pep rally, a group of sophomore students organized a free raffle for prizes. They claim that they put the names of all of the students in the school in the basket and that they randomly drew 36 names out of this basket. Of the prize winners, 6 were freshmen, 14 were sophomores, 9 were juniors, and 7 were seniors. The results do not seem that random to you. You think it is a little fishy that sophomores organized the raffle and also won the most prizes. Your school is composed of 30% freshmen, 25% sophomores, 25% juniors, and 20% seniors. (a) What are the expected frequencies of winners from each class? (b) Conduct a significance test to determine whether the winners of the prizes were distributed throughout the classes as would be expected based on the percentage of students in each group. Report your Chi Square and p values. (c) What do you conclude? |
Algebraic Expression: |
276) Problem #PRAE6N9 "PRAE6N9 - 145482 - Some parents of t..." |
Some parents of the West Bay little leaguers think that they are noticing a pattern. There seems to be a relationship between the number on the kids' jerseys and their position. These parents decide to record what they see. The hypothetical data appear below. Conduct a Chi Square test to determine if the parents' suspicion that there is a relationship between jersey number and position is right. Report your Chi Square and p values.
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Algebraic Expression: |
277) Problem #PRAE6PA "PRAE6PA - 145483 - True/false: A Chi..." |
True/false: A Chi Square distribution with 2 df has a larger mean than a Chi Square distribution with 12 df. |
Algebraic Expression: |
278) Problem #PRAE6PB "PRAE6PB - 145484 - True/false: A Chi..." |
True/false: A Chi Square test is often used to determine if there is a significant relationship between two continuous variables. |
Algebraic Expression: |
279) Problem #PRAE6PG "PRAE6PG - 145489 - Problem #145489" |
Algebraic Expression:
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280) Problem #PRAE59Z "PRAE59Z - 145102 - Which variables a..." |
Which variables are the participant variables? (They act as independent variables in this study.) |
Algebraic Expression: |
281) Problem #PRAE592 "PRAE592 - 145103 - What are the depe..." |
What are the dependent variables? |
Algebraic Expression: |
282) Problem #PRAE594 "PRAE594 - 145105 - Is Anger-Out a qu..." |
Is Anger-Out a quantitative or qualitative variable? |
Algebraic Expression: |
283) Problem #PRAE595 "PRAE595 - 145106 - Does Anger-Out ha..." |
Does Anger-Out have a postive skew, a negative skew, or no skew? |
Algebraic Expression: |
284) Problem #PRAE596 "PRAE596 - 145107 - What are the mean..." |
What are the mean and standard deviation of the Anger-Out scores? Compute a confidence interval for the mean Anger-Out score. |
Algebraic Expression: |
285) Problem #PRAE597 "PRAE597 - 145108 - Is there a differ..." |
A)
Is there a difference in how much males and females use aggressive behavior to improve an angry mood? For the "Anger-Out" scores: Create parallel box plots. |
Algebraic Expression: |
B)
Create a back-to-back stem and leaf displays (You may have trouble finding a computer to do this so you may have to do it by hand). |
Algebraic Expression: |
C)
Compute a confidence interval on the difference between means. |
Algebraic Expression: |
D)
Compute a significance test on the difference between means using a t test. |
Algebraic Expression: |
E)
Compute a significance test on the difference between means using ANOVA.Compare your results to (d) above. |
Algebraic Expression: |
286) Problem #PRAE6TV "PRAE6TV - 145625 - What is the range..." |
What is the range of the Anger-In scores? What is the interquartile range? |
Algebraic Expression: |
287) Problem #PRAE62N "PRAE62N - 145835 - Create parallel b..." |
Create parallel box plots for the Anger-In scores by sports participation. |
Algebraic Expression: |
288) Problem #PRAE62P "PRAE62P - 145836 - Calculate the con..." |
Calculate the confidence interval for the difference between mean Anger-In score for the athletes and non-athletes. What can you conclude? |
Algebraic Expression: |
289) Problem #PRAE62Q "PRAE62Q - 145837 - Plot a histogram ..." |
Plot a histogram of the distribution of the Control-Out scores. |
Algebraic Expression: |
290) Problem #PRAE62R "PRAE62R - 145838 - What is the overa..." |
What is the overall mean Control-Out score? What is the mean Control-Out score for the athletes? What is the mean Control-Out score for the non-athletes? |
Algebraic Expression: |
291) Problem #PRAE62S "PRAE62S - 145839 - Determine if the ..." |
Determine if the difference in the mean Control-Out score for athletes and non-athletes is statistically significant. |
Algebraic Expression: |
292) Problem #PRAE62T "PRAE62T - 145840 - Create a bar grap..." |
Create a bar graph comparing the mean Control-In score for the athletes and the non-athletes. What would be a better way to display this data? |
Algebraic Expression: |
293) Problem #PRAE62U "PRAE62U - 145841 - What is the varia..." |
What is the variance of the Control-In scores for the athletes? What is the variance of the Control-In scores for the non-athletes? |
Algebraic Expression: |
294) Problem #PRAE62V "PRAE62V - 145842 - What is the stand..." |
What is the standard error of the mean for the Control-In scores for the athletes? What is the standard error of the mean of the Control-In scores for the non-athletes? Why is it smaller for non-athletes? |
Algebraic Expression: |
295) Problem #PRAE62W "PRAE62W - 145843 - Do athletes or no..." |
Do athletes or non-athletes calm down more when angry? Conduct a t test to see if the difference between groups in Control-In scores is statistically significant. |
Algebraic Expression: |
296) Problem #PRAE62X "PRAE62X - 145844 - Plot parallel box..." |
Plot parallel box plots of the Anger Expression Index by sports participation. Does it look like there are any outliers? Which group reported expressing more anger? |
Algebraic Expression: |
297) Problem #PRAE62Y "PRAE62Y - 145845 - Plot parallel box..." |
Plot parallel box plots of the Anger Expression Index by gender. |
Algebraic Expression: |
298) Problem #PRAE62Z "PRAE62Z - 145846 - Using the Anger E..." |
Using the Anger Expression Index as the dependent variable, perform a 2x2 ANOVA with gender and sports participation as the two factors. Do athletes and non-athletes differ significantly in how much anger they express? Do the genders differ significantly in Anger Expression Index? Is the effect of sports participation significantly different for the two genders? |
Algebraic Expression: |
299) Problem #PRAE622 "PRAE622 - 145847 - What is the corre..." |
What is the correlation between the Control-In and Control-Out scores? Is this correlation statistically significant at the 0.01 level? |
Algebraic Expression: |
300) Problem #PRAE623 "PRAE623 - 145848 - Would you expect ..." |
Would you expect the correlation between the Anger-Out and Control-Out scores to be positive or negative? Compute this correlation. |
Algebraic Expression: |
301) Problem #PRAE624 "PRAE624 - 145849 - Find the regressi..." |
A)
Find the regression line for predicting Anger-Out from Control-Out. What is the slope? |
Algebraic Expression: |
B)
What is the intercept? |
Algebraic Expression: |
C)
Is the relationshipt at least approximately linear? |
Algebraic Expression: |
D)
Test to see if the slope is significantly different from 0. |
Algebraic Expression: |
E)
What is the standard error of the estimate? |
Algebraic Expression: |
302) Problem #PRAE58P "PRAE58P - #1 Case Study C: Physician's Reactions" |
Create box plots comparing the time expected to be spent with the average-weight and overweight patients. |
Algebraic Expression: |
303) Problem #PRAE58R "PRAE58R - #2 Case Study C: Physician's Reaction" |
What is the mean expected time spent for the average- weight patients? What is the mean expected time spent for the overweight patients? |
Algebraic Expression: |
304) Problem #PRAE58S "PRAE58S - #3 Case Study C: Physician's Reaction" |
What is the difference in means between the groups? Approximately how many standard deviations do the means differ? |
Algebraic Expression: |
305) Problem #PRAE58U "PRAE58U - #4 Case Study C: Physician's Reaction" |
Plot histograms of the time spent with the average-weight and overweight patients. |
Algebraic Expression: |
306) Problem #PRAE58V "PRAE58V - #5 Case Study C: Physician's Reaction" |
To which group does the patient with the highest expected time belong? |
Algebraic Expression: |
307) Problem #PRAE58Z "PRAE58Z - #6 Case Study C: Physician's Reaction" |
Perform an independent samples t test comparing the time spent with the average-weight patients as compared to the time spent with the overweight patients. Is this difference statistically significant? |
Algebraic Expression: |
308) Problem #PRAE582 "PRAE582 - #7 Case Study C: Physician's Reaction" |
What is the confidence interval on the difference between mean time spent with each group? |
Algebraic Expression: |
309) Problem #PRAE57Y "PRAE57Y - 145039 - #1 Case Study D: Teacher Rating" |
What is the independent variable in this study? |
Algebraic Expression: |
310) Problem #PRAE574 "PRAE574 - #2 Case Study D: Teacher Ratings" |
Plot stem and leaf displays of the ratings for each condition. |
Algebraic Expression: |
311) Problem #PRAE577 "PRAE577 - #3 Case Study D:Teacher Ratings" |
What is the standard deviation of the ratings in the charismatic-reputation condition? What is the standard deviation of the ratings in the punitive-reputation condition? |
Algebraic Expression: |
312) Problem #PRAE579 "PRAE579 - #4 Case Study D: Teacher Ratings" |
Plot side-by-side box plots for the ratings by condition. |
Algebraic Expression: |
313) Problem #PRAE58A "PRAE58A - #5 Case Study D: Teacher Ratings" |
In which of the two conditions are there outliers? |
Algebraic Expression: |
314) Problem #PRAE58C "PRAE58C - #6 Case Study D: Teacher Ratings" |
Conduct an independent-samples t-test to examine the difference between the mean ratings of the charismatic-reputation condition and the punitive-reputation condition. Is the difference in mean ratings statistically significant? What can you conclude? |
Algebraic Expression: |
315) Problem #PRAE58F "PRAE58F - #7 Case Study D: Teacher Ratings" |
Compute a confidence interval on the difference between the means of the two conditions. |
Algebraic Expression: |
316) Problem #PRAE68B "PRAE68B - 146011 - #1 Case Study E: Mediterranean Health and Diet" |
What percentage of people on the AHA diet had some sort of illness or death? Use the following information. Frequencies
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Algebraic Expression: |
317) Problem #PRAE68C "PRAE68C - #2 Case Study E" |
What percentage of people on the Mediterranean diet had some sort of illness or death? Frequencies
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Algebraic Expression: |
318) Problem #PRAE68D "PRAE68D - #3 Case Study E" |
Conduct a Pearson Chi-Square test to determine if there is any relationship between diet and outcome. Frequencies
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Ungraded Open Response: |
319) Problem #PRAE68E "PRAE68E - #4 Case Study E" |
Compute a 95% confidence interval on the proportion of people who are healthy on the AHA diet. Frequencies
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Algebraic Expression: |
320) Problem #PRAE59Y "PRAE59Y - smiles and leniency 1" |
1. Create parallel boxplots for the four conditions. |
Algebraic Expression: |
321) Problem #PRAE598 "PRAE598 - smiles and leniency 2" |
2.Find the mean, median, standard deviation, and interquartile range for each group. |
Algebraic Expression: |
322) Problem #PRAE599 "PRAE599 - 145110 - smiles and leniency 3" |
3.Create back-back stem and leaf displays for the false smile and neutral conditions (It may be hard to find a computer program to do this for you, so be prepared to do it by hand). |
Algebraic Expression: |
323) Problem #PRAE6AB "PRAE6AB - smiles and leniency 4" |
4.Compute a one-way ANOVA. |
Algebraic Expression: |
324) Problem #PRAE8JH "PRAE8JH - Problem #147288" |
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Algebraic Expression: |
325) Problem #PRAE8JJ "PRAE8JJ - Problem #147289" |
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Algebraic Expression: |
326) Problem #PRAE8JK "PRAE8JK - Problem #147290" |
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Algebraic Expression: |
327) Problem #PRAE8JN "PRAE8JN - Problem #147292" |
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Algebraic Expression: |
328) Problem #PRAE8JP "PRAE8JP - Problem #147293" |
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Algebraic Expression: |
329) Problem #PRAE8JR "PRAE8JR - Problem #147295" |
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Algebraic Expression: |
330) Problem #PRAE8JV "PRAE8JV - Problem #147299" |
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Algebraic Expression: |
331) Problem #PRAE8JW "PRAE8JW - Problem #147300" |
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Algebraic Expression: |
332) Problem #PRAE8JX "PRAE8JX - Problem #147301" |
What percentage of men disagreed on some level (gave ratings of 1, 2, or 3) that animal research was necessary? |
Algebraic Expression: |
333) Problem #PRAE8JY "PRAE8JY - Problem #147302" |
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Algebraic Expression: |
334) Problem #PRAE8JZ "PRAE8JZ - Problem #147303" |
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Algebraic Expression: |
335) Problem #PRAE8J2 "PRAE8J2 - Problem #147304" |
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Algebraic Expression: |
336) Problem #PRAE8J3 "PRAE8J3 - Problem #147305" |
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Algebraic Expression: |
337) Problem #PRAE8J5 "PRAE8J5 - Problem #147307" |
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Algebraic Expression: |
338) Problem #PRAE8J7 "PRAE8J7 - Problem #147309" |
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Algebraic Expression: |
339) Problem #PRAE8J8 "PRAE8J8 - Problem #147310" |
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Algebraic Expression: |
340) Problem #PRAE8J9 "PRAE8J9 - 147311 - What is the mean ..." |
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Algebraic Expression: |
341) Problem #PRAE8KB "PRAE8KB - Problem #147313" |
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Algebraic Expression: |
342) Problem #PRAE8KD "PRAE8KD - Problem #147315" |
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Algebraic Expression: |
343) Problem #PRAE8KE "PRAE8KE - Problem #147316" |
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Algebraic Expression: |
344) Problem #PRAE8KG "PRAE8KG - Problem #147318" |
What is the correlation between the participants' correct number of responses after taking the placebo and their correct number of responses after taking 0.60 mg/kg of MPH? |
Algebraic Expression: |
345) Problem #PRAE8KJ "PRAE8KJ - Problem #147320" |
Perform a repeated measures ANOVA.
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Algebraic Expression: |
346) Problem #PRAE8KK "PRAE8KK - Problem #147321" |
Test the difference betwen the d0 and d60 conditions using a sign test |
Algebraic Expression: |
347) Problem #PRAE7V8 "PRAE7V8 - 146659 - The "weapons effe..." |
The "weapons effect" is the finding that the presence of a weapon or even a picture of a weapon can cause people to behave more aggressively. Although once a controversial finding, the weapons effect is now a well-established phenomenon. Based on this, Anderson, Benjamin, and Bartholow (1998) hypothesize that the presence of a weapon-word prime (such as "dagger" or "bullet") should increase the accessibility of an aggressive word (such as "destroy" or "wound"). The accessibility of a word can be measured by the time it takes to name a word presented on computer screen. The subjects were undergraduate students ranging in age from 18 to 24 years. They were told that the purpose of this study was to test reading ability of various words. On each of the 192 trials, a computer presented a priming stimulus word (either a weapon or non-weapon word) for 1.25 seconds, a blank screen for 0.5 seconds, and then a target word (aggressive or non-aggressive word). Each subject named both aggressive and non-aggressive words following both weapon and non-weapon "primes." The experimenter instructed the subjects to read the first word to themselves and then to read the second word out loud as quickly as they could. The computer recorded response times and computed mean response times for each participant for each of the four conditions.
Create a box plot of the distribution of reaction times for each condition (aw, an, cw, and cn). |
Algebraic Expression: |
348) Problem #PRAE7WA "PRAE7WA - 146661 - Create a histogra..." |
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Algebraic Expression: |
349) Problem #PRAE7WB "PRAE7WB - 146662 - What is the mean ..." |
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Algebraic Expression: |
350) Problem #PRAE7WC "PRAE7WC - 146663 - Recall that the h..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
C)
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Algebraic Expression: |
D)
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Algebraic Expression: |
E)
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Algebraic Expression: |
F)
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Algebraic Expression: |
351) Problem #PRAE7WD "PRAE7WD - 146664 - Compare the resul..." |
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Algebraic Expression: |
352) Problem #PRAE7WF "PRAE7WF - 146666 - Compute cn-cw for..." |
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Algebraic Expression: |
353) Problem #PRAE7WH "PRAE7WH - 146668 - Subtract the diff..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
C)
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Algebraic Expression: |
D)
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Algebraic Expression: |
E)
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Algebraic Expression: |
354) Problem #PRAE7WJ "PRAE7WJ - 146669 - Compute a 2x2 wit..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
C)
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Algebraic Expression: |
355) Problem #PRAE7WM "PRAE7WM - 146671 - When deciding whe..." |
When deciding whether to admit an applicant, colleges take lots of factors, such as grades, sports, activities, leadership positions, awards, teacher recommendations, and test scores, into consideration. Using SAT scores as a basis of whether to admit a student or not has created some controversy. Among other things, people question whether the SATs are fair and whether they predict college performance.
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Algebraic Expression: |
356) Problem #PRAE7WP "PRAE7WP - 146673 - What is the corre..." |
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Algebraic Expression: |
357) Problem #PRAE7WR "PRAE7WR - 146675 - Find the regressi..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
C)
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Algebraic Expression: |
D)
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Algebraic Expression: |
358) Problem #PRAE7WT "PRAE7WT - 146677 - What is the mean ..." |
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Algebraic Expression: |
359) Problem #PRAE7WU "PRAE7WU - 146678 - What are the stan..." |
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Algebraic Expression: |
360) Problem #PRAE7WW "PRAE7WW - 146680 - What would you ex..." |
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Algebraic Expression: |
361) Problem #PRAE7WX "PRAE7WX - 146681 - What is the corre..." |
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Algebraic Expression: |
362) Problem #PRAE7WZ "PRAE7WZ - 146683 - Did the students ..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
363) Problem #PRAE7W2 "PRAE7W2 - 146684 - Find the regressi..." |
A)
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Algebraic Expression: |
B)
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Algebraic Expression: |
C)
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Algebraic Expression: |
D)
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Algebraic Expression: |
364) Problem #PRAE6KY "PRAE6KY - 145411 - What are the mean..." |
What are the mean and median ages? |
Algebraic Expression: |
365) Problem #PRAE6K3 "PRAE6K3 - 145414 - Plot a histogram ..." |
Plot a histogram of the distribution of the ages. Using this plot and the information from #1, determine if the age variable is normally distributed, positively skewed, or negatively skewed. |
Algebraic Expression: |
366) Problem #PRAE6K4 "PRAE6K4 - 145415 - What is the mean ..." |
What is the mean percentage of time that the participants in this study spend traveling on public transportation during inclement weather? |
Algebraic Expression: |
367) Problem #PRAE6NV "PRAE6NV - 145470 - What is the stand..." |
What is the standard deviation of Pubtran? |
Algebraic Expression: |
368) Problem #PRAE6NW "PRAE6NW - 145471 - What is the corre..." |
What is the correlation between age and how often the person chooses to drive in inclement weather? Is this correlation statistically significant at the .01 level? Are older people more or less likely to report that they drive in inclement weather? |
Algebraic Expression: |
369) Problem #PRAE6NX "PRAE6NX - 145472 - Compute a 95% con..." |
Compute a 95% confidence interval on the correlation between age and how often the person chooses to drive in inclement weather. |
Algebraic Expression: |
370) Problem #PRAE6NY "PRAE6NY - 145473 - Is there a gender..." |
A)
Is there a gender difference in the likelihood to drive in inclement weather? Do the following exercises to find out.Plot side-by-side (parallel) box plots of Cho2drive by gender. |
Algebraic Expression: |
B)
What is the mean difference in how much men and women choose to drive in inclement weather? |
Algebraic Expression: |
C)
Perform an independent samples t test. |
Algebraic Expression: |
D)
Is there any evidence that the assumption of homogeneity of variance is violated? |
Algebraic Expression: |
E)
What is the 95% confidence interval for the mean difference? |
Algebraic Expression: |
F)
Can you reject the null hypothesis if α = .05? |
Algebraic Expression: |
371) Problem #PRAE6NZ "PRAE6NZ - 145474 - What is the corre..." |
What is the correlation between how often a person chooses to drive in inclement weather and the percentage of accidents the person believes occur in inclement weather? Is this correlation significantly different from 0? |
Algebraic Expression: |
372) Problem #PRAE6N2 "PRAE6N2 - 145475 - What is the corre..." |
What is the correlation between how often someone rides public transportation in inclement weather (Pubtran) and what percentage of accidents the person thinks occur in inclement weather (Accident)? |
Algebraic Expression: |
373) Problem #PRAE6N3 "PRAE6N3 - 145476 - Use linear regres..." |
A)
Use linear regression to predict how often someone rides public transportation in inclement weather from what percentage of accidents that person thinks occur in inclement weather. (Pubtran by Accident) Create a scatter plot of this data and add a regression line. |
Algebraic Expression: |
B)
What is the slope? |
Algebraic Expression: |
C)
What is the intercept? |
Algebraic Expression: |
D)
Is the relationship at least approximately linear? |
Algebraic Expression: |
E)
Test if the slope is significantly different from 0. |
Algebraic Expression: |
F)
Comment on possible assumption violations for the test of the slope. |
Algebraic Expression: |
G)
What is the standard error of the estimate? |
Algebraic Expression: |
374) Problem #PRAE7AV "PRAE7AV - 146090 - Variab..." |
1. Compute the mean for WORDS. |
Algebraic Expression: |
375) Problem #PRAE7AW "PRAE7AW - 146091 - Descriptions of..." |
Descriptions of Variables
Compute the mean and standard deviation for "colors." |
Algebraic Expression: |
376) Problem #PRAE7AX "PRAE7AX - 146092 - Descriptions of V..." |
Descriptions of Variables
3. Create parallel box plots for males and females for "colors." |
Algebraic Expression: |
377) Problem #PRAE7AY "PRAE7AY - 146093 - Descriptions of V..." |
Descriptions of Variables
4. Create back-to-back stem and leaf plots for "colors" as a function of gender (You may have to do this by hand). |
Algebraic Expression: |
378) Problem #PRAE7AZ "PRAE7AZ - 146094 - Descriptions of..." |
Descriptions of Variables
5. Create a stem and leaf plot for "interference." |
Algebraic Expression: |
379) Problem #PRAE7A2 "PRAE7A2 - 146095 - Descript..." |
Descriptions of Variables
6. Create a scatterplot showing "color" on the Y-axis and "words" on the X-axis. |
Algebraic Expression: |
380) Problem #PRAE7A3 "PRAE7A3 - 146096 - Descriptions of..." |
Descriptions of Variables
7. Compute the correlation between "color" and "words. |
Algebraic Expression: |
381) Problem #PRAE7A4 "PRAE7A4 - 146097 - Descript..." |
Descriptions of Variables
8. Compute the correlation between "color" and "words" using only the 23 fastest color-namers. |
Algebraic Expression: |
382) Problem #PRAE7A5 "PRAE7A5 - 146098 - Descriptions of..." |
Descriptions of Variables
9. Do a t test comparing males and females on "color." |
Algebraic Expression: |
383) Problem #PRAE7A6 "PRAE7A6 - 146099 - Descriptions of..." |
Descriptions of Variables
10. Compute the 95% confidence interval for "interference." |
Algebraic Expression: |
384) Problem #PRAE7A7 "PRAE7A7 - 146100 - Descriptions of..." |
Descriptions of Variables
11. Do a t-test of the difference between "colors" and "interference." |
Algebraic Expression: |
385) Problem #PRAE7A8 "PRAE7A8 - 146101 - Descriptions of..." |
Descriptions of Variables
12. Do a 2 x 3 ANOVA with gender as the between subject variable and task (Colors, Words, Interference) as within-subject variables. |
Algebraic Expression: |
386) Problem #PRAE8AC "PRAE8AC - 147035 - How many hours a ..." |
How many hours a day on average that each child watches television? What is the range of television hours watched? |
Exact Match (case sensitive):
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387) Problem #PRAE8AE "PRAE8AE - 147037 - In computing the ..." |
In computing the mean hours watched, were there any apparent outliers? What effect might this have on the mean hours watched? |
Algebraic Expression:
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388) Problem #PRAE8AH "PRAE8AH - 147040 - Recompute the mea..." |
Recompute the mean without the outlier(s). |
Algebraic Expression:
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389) Problem #PRAE8AD "PRAE8AD - 147036 - What is the overa..." |
What is the overall correlation between the numbers of hours of TVhours watched and the obedience? What is the correlation between TV hours watched and attitude? |
Algebraic Expression: |
390) Problem #PRAE8AF "PRAE8AF - 147038 - Describe the rela..." |
Describe the relationships indicated in question 4. Are either of these correlations statistically significant? |
Algebraic Expression: |
391) Problem #PRAE8AG "PRAE8AG - 147039 - Do a simple frequ..." |
Do a simple frequency count on attitude. What fundamental problem does this data present for the hypothesis? What sampling changes could be made to better test the hypothesis that "children who watch more TV are more aggressive?" |
Algebraic Expression: |
392) Problem #PRAE686 "PRAE686 - 146037 - WEIGHT RELATE..." |
A)
Descriptions of Variables
What is/are the independent variable(s) in this study? |
Algebraic Expression: |
B)
What is/are the dependent variable(s)? |
Algebraic Expression: |
393) Problem #PRAE7CG "PRAE7CG - 146140 - What is the mean ..." |
A)
What is the mean rating of job qualification? |
Algebraic Expression: |
B)
What is the standard deviation? |
Algebraic Expression: |
C)
Does "qualified" appear to be normally distributed? |
Algebraic Expression: |
394) Problem #PRAE7CK "PRAE7CK - 146143 - If a participant ..." |
If a participant from this sample were picked at random, what is the probability that he/she would have rated the qualification of the applicant as 7 or higher? |
Algebraic Expression: |
395) Problem #PRAE7CM "PRAE7CM - 146144 - Pretend the distr..." |
Pretend the distribution of "qualified" is normally distributed (with same mean and standard deviation you computed in #2). Now what is the probability of selecting a participant who gave a rating of 7 or higher? |
Algebraic Expression: |
396) Problem #PRAE7CQ "PRAE7CQ - 146147 - Describe the desi..." |
A)
Describe the design of this study. |
Algebraic Expression: |
B)
What type of ANOVA would you use? |
Algebraic Expression: |
C)
How many factors are there? |
Algebraic Expression: |
D)
How many levels does each factor have? |
Algebraic Expression: |
397) Problem #PRAE7CR "PRAE7CR - 146148 - Make an interacti..." |
A)
Make an interaction plot of the data. |
Algebraic Expression: |
B)
Based on this graph, do you think there are main effects? |
Algebraic Expression: |
C)
Do you think there is an interaction? |
Algebraic Expression: |
398) Problem #PRAE7CS "PRAE7CS - 146149 - Conduct a 2-way A..." |
A)
Conduct a 2-way ANOVA. What is the best estimate of the population variance? |
Algebraic Expression: |
B)
Look at the main effect of "weight".
|
Algebraic Expression: |
C)
Look at the main effect of "relate".
|
Algebraic Expression: |
D)
Look at the interaction between "weight" and "relate".
|
Algebraic Expression: |
E)
What do these results mean? |
Algebraic Expression: |
399) Problem #PRAE68G "PRAE68G - #1 Case Study P: Shaking and Stirring Martinis" |
What is the null hypothesis? |
Multiple Choice: |
400) Problem #PRAE68H "PRAE68H - #2 Case Study P" |
What is the probability of being right 13 or more out of 16 if Mr. Bond were only guessing? |
Algebraic Expression: |
401) Problem #PRAE68J "PRAE68J - #3 Case Study P" |
What is the probability of being right (3 or fewer times) or (13 or more times) if Mr. Bond were only guessing? |
Algebraic Expression: |
402) Problem #PRAE68K "PRAE68K - #4 Case Study P" |
What is the one-tailed probability? |
Algebraic Expression: |
403) Problem #PRAE6AZ "PRAE6AZ - 145133 - Which of the foll..." |
Which of the following would make the sampling distribution of the sample mean narrower? Check all answers that apply. |
Check All That Apply:
|
404) Problem #PRAE7XY "PRAE7XY - Estimating a Population Mean: Small Samples Problems" |
A)
A random sample of 121 students from the UCLA was selected to estimate the average ACT score of all UCLA students. The average for the sample was 23.4 and the sample standard deviation was 3.65. If you wanted to calculate a more precise and accurate prediction of the average ACT score of UCLA students, which one of the following would be the best thing to do? |
Multiple Choice:
|
B)
The average standardized math score for eighth graders in the state of California is 70 and the standard deviation is 10. We want to find out if the average standardized math score in district A is higher than the average score for the state of California. The mean for a random sample of 36 students from this district is 72. What is the best response? |
Multiple Choice:
|
405) Problem #PRAE6A6 "PRAE6A6 - 145138 - Suppose you were ..." |
Suppose you were hired to conduct a study to find out which of two brands of soda college students think taste better. In your study, students are given a blind taste test. They rate one brand and then rated the other, in random order. The ratings are given on a scale of 1 (awful) to 5 (delicious). Which type of test would be the best to compare these ratings? |
Multiple Choice:
|
406) Problem #PRAE6BB "PRAE6BB - 145143 - USA Today's AD Tr..." |
USA Today's AD Track examined the effectiveness of the new ads involving the Pets.com Sock Puppet (which is now extinct). In particular, they conducted a nationwide poll of 428 adults who had seen the Pets.com ads and asked for their opinions. They found that 36% of the respondents said they liked the ads. Suppose you increased the sample size for this poll to 1000, but you had the same sample percentage who like the ads (36%). How would this change the p-value of the hypothesis test you want to conduct? |
Multiple Choice:
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407) Problem #PRAE6BE "PRAE6BE - 145146 - A marketing direc..." |
A marketing director for a radio station collects a random sample of three hundred 18 to 25 year-olds and two hundred and fifty 25 to 40 year-olds. She records the percent of each group that had purchased music online in the last 30 days. She performs a hypothesis test, and the p-value of her test turns out to be 0.15. From this she should conclude: |
Multiple Choice:
|
408) Problem #PRAE6BG "PRAE6BG - 145148 - If we want to est..." |
If we want to estimate the mean difference in scores on a pre-test and post-test for a sample of students, how should we proceed? |
Multiple Choice:
|
409) Problem #PRAE6BN "PRAE6BN - 145153 - The paint used to..." |
The paint used to make lines on roads must reflect enough light to be clearly visible at night. Let mu denote the true average reflectometer reading for a new type of paint under consideration. A test of the null hypothesis that mu = 20 versus the alternative hypothesis that mu > 20 will be based on a random sample of size n from a normal population distribution. In which of the following scenarios is there significant evidence that mu is larger than 20? (i) n=15, t=3.2, alpha=0.05 (ii) n=9, t=1.8, alpha=0.01 (iii) n=24, t=-0.2, alpha=0.01 |
Multiple Choice:
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410) Problem #PRAE6BR "PRAE6BR - 145156 - The average lengt..." |
The average length of time required to complete a certain aptitude test is claimed to be 80 minutes. A random sample of 25 students yielded an average of 86.5 minutes and a standard deviation of 15.4 minutes. If we assume normality of the population distribution, is there evidence to reject the claim? (Select all that applies). |
Multiple Choice:
|
411) Problem #PRAE6BW "PRAE6BW - 145161 - We observe the ma..." |
We observe the math self-esteem scores from a random sample of 25 female students. How should we determine the probable values of the population mean score for this group? |
Multiple Choice:
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412) Problem #PRAE6B6 "PRAE6B6 - 145169 - Food inspectors i..." |
Food inspectors inspect samples of food products to see if they are safe. This can be thought of as a hypothesis test where H0: the food is safe, and H1: the food is not A. If you are a consumer, which type of error would be the worst one for the inspector to make, the type I or type II error? |
Multiple Choice:
|
413) Problem #PRAE7DS "PRAE7DS - 146180 - Estimating a Popu..." |
Estimating a Population Variance Problem 1 We have discussed that the standard deviation of the distribution of sample percentages or SE(p hat) is calculated by taking the square root of p hat * (1 - p hat)/ N, where p hat is the proportion in the sample and N is sample size What does SE(p hat) show? |
Multiple Choice:
|
414) Problem #PRAE7DV "PRAE7DV - 146183 - Student's T Distr..." |
Student's T Distribution Problem 1 Estimate the critical value of t for a 95% confidence interval with df = 15 |
Multiple Choice:
|
415) Problem #PRAE7DY "PRAE7DY - 146186 - Student's T Distr..." |
Student's T Distribution Problem 2 How do the shape, center, and spread of a t-model change as its degrees of freedom increase? |
Multiple Choice:
|
416) Problem #PRAE6A7 "PRAE6A7 - 145139 - If sampling distr..." |
If sampling distributions of sample means are examined for samples of size 1, 5, 10, 16 and 50, you will notice that as sample size increases, the shape of the sampling distribution appears more like that of the: |
Multiple Choice:
|
417) Problem #PRAE6A9 "PRAE6A9 - 145141 - All other things ..." |
All other things being equal, as the sample size increases, the standard error of a statistic |
Multiple Choice:
|
418) Problem #PRAE6BD "PRAE6BD - 145145 - Suppose that the ..." |
Suppose that the distribution of X in the population is strongly skewed to the left. If you took 200 independent and random samples of size 3 from this population, calculated the mean for each of the 200 samples, and drew the distribution of the sample means, what would the sampling distribution of the means look like? |
Multiple Choice:
|
419) Problem #PRAE6BF "PRAE6BF - 145147 - Is the following ..." |
Is the following approach a correct method for teaching the CLT to a class of 40 students? Ask each of the 40 students to: 1) Ask 50 of their friends, classmates, and relatives for their weight in pounds. 2) Calculate the mean weight or Xbar 3) Draw the histogram of the sample means using the 40 means. |
Multiple Choice:
|
420) Problem #PRAE6BM "PRAE6BM - 145152 - If you take all s..." |
If you take all samples of a particular size from a particular population, find the mean of each sample, and then plot the distribution of the means, what have you created? |
Multiple Choice:
|
421) Problem #PRAE6BP "PRAE6BP - 145154 - A study was plann..." |
A study was planned to examine the length of a certain species of fish on Gull Lake. The initial plan was to take a random sample of 100 fish from this lake using a special net, and examine our results. We are also interested in investigating fish lengths in Lake Monster. The fish lengths in Lake Monster have a standard deviation that is twice as big as that on Gull Lake. Suppose you still wanted to get an accurate estimate of the mean fish length for Lake Monster (within 0.25 inches). Select the answer that best describes the sample size we need: |
Multiple Choice:
|
422) Problem #PRAE6BS "PRAE6BS - 145157 - The LAPD has been..." |
The LAPD has been testing a new system of catching speeders on the 405 over the last 10 months. They wanted to see if they really were catching more speeders, so each month they took 20 samples (with replacement) from the tickets issued in this program . Because their sample sizes were always one-fifth of the tickets, they increased in size each month. How did the sampling distribution of the mean change over the 10 months? |
Multiple Choice:
|
423) Problem #PRAE6BX "PRAE6BX - 145162 - What is a practic..." |
What is a practical application of the Central Limit Theorem? |
Multiple Choice:
|
424) Problem #PRAE6B2 "PRAE6B2 - 145165 - A researcher conv..." |
A researcher converts 100 lung capacity measurements to z-scores. The lung capacity measurements do not follow a normal distribution. What can we say about the standard deviation of the 100 z-scores? |
Multiple Choice:
|
425) Problem #PRAE6B5 "PRAE6B5 - 145168 - In Chesapeake Bay..." |
In Chesapeake Bay, complex changes in salinity are caused by the mixture of fresh water and sea water during the diurnal tidal cycle. The fresh water from the Chesapeake River floats across the denser brine in the bay, and during low tide it travels farther down the estuary. There is a counterflow, however, along the bottom that carries the dense marine water up the bay during the waning tide. The surface salinity measurements (in parts per thousand) taken at station 11, offshore from Annapolis, Maryland, on July 3-4, 1927 are collected. The normal probability plot and the histogram show that the data are very skewed. Under these circumstances, to conduct a test of hypotheses with this sample of measurements, what extra condition would we need? |
Multiple Choice:
|
426) Problem #PRAE6B8 "PRAE6B8 - 145171 - A polling agency ..." |
A polling agency has been hired to predict the proportion of voters who favor a certain candidate. The polling agency picks a random sample of 1000 voters of which 400 indicate that they favor the candidate. If they increase the sample size to 2000, how does the standard error change? |
Multiple Choice:
|
427) Problem #PRAE6BV "PRAE6BV - 145160 - A 1996 poll of 1,..." |
A 1996 poll of 1,200 African American adults found that 708 think that the American dream has become impossible to achieve. The New Yorker magazine editors want to estimate the proportion of all African American adults who feel this way. Which of the following is an approximate 90% confidence interval for the proportion of all African American adults who feel this way? |
Multiple Choice:
|
428) Problem #PRAE6B3 "PRAE6B3 - 145166 - True or False: In..." |
True or False: In a well-designed sample survey like the Current Population Survey, the observed sample percentage (e.g, percentage unemployed) is equal to the population percentage. Thus, it is appropriate to just report the sample percentage, without any measure of accuracy (i.e. without the margin of error). |
Multiple Choice:
|
429) Problem #PRAE6B4 "PRAE6B4 - 145167 - The BBC news does..." |
The BBC news does a story and at one point the reporter says: "A polling agency reports that the percentage of the American public who agree we should spend more money on the mental health of the war veterans is 42% +/- 3%." |
Multiple Choice:
|
430) Problem #PRAE6B7 "PRAE6B7 - 145170 - A school district..." |
A school district is worried that too many students are failing the high school exit exam. In a random sample of 60 high school students, there are 9 students who fail the exit exam. Administrators want to estimate the percentage of the students who fail with a margin of error of 3% and confidence level of 90%. How many students should they sample for a thorough investigation of the problem? |
Multiple Choice:
|
431) Problem #PRAE6CA "PRAE6CA - 145173 - A major newspaper..." |
A major newspaper wants to hire a polling agency to predict who will be the next governor. Agency A proposes to do the job with a random sample of 5000 voters at a cost of $50K (K = one thousand). Agency B proposes to do the job with a random sample of 7500 voters at a cost of $75K. Assume both agencies find the percentage of voters to be 40% and both use the normal model to calculate the 95% interval. Which agency will you hire? Hint: Compare the margin of error for the two agencies and the relative costs before making your decision. |
Multiple Choice:
|
432) Problem #PRAE6DS "PRAE6DS - 145219 - An investigator m..." |
An investigator made a careful sample survey to estimate the prevalence of drug use at UCLA. Two assistants were stationed in front of Ackerman Union and instructed to interview all students who passed through at specified times. As it turned out, 39% of 369 students interviewed said they had used ecstasy at least once. Which of the following statements is correct? |
Multiple Choice:
|
433) Problem #PRAE6DU "PRAE6DU - 145221 - A survey is carri..." |
A survey is carried out at a university to estimate the percentage of undergraduates living at home during the current term. What is the population? What is the parameter? |
Multiple Choice:
|
434) Problem #PRAE6DV "PRAE6DV - 145222 - A recent Gallup P..." |
A recent Gallup Poll found that 23% of senior citizens exercise at least 3 times a week. The number 23% is |
Multiple Choice:
|
435) Problem #PRAE6DW "PRAE6DW - 145223 - Market researcher..." |
Market researchers are interested in determining the true proportion of college students who use their ATM each week. Suppose they take 100 random samples of 40 college students and count those who use their ATM this week. Describe the distribution of proportions selected from each of these samples. |
Multiple Choice:
|
436) Problem #PRAE67S "PRAE67S - 145994 - Suppose that you ..." |
Suppose that you and everyone else in a large stat class each selects a random sample of 50 Skittles candies, counts the greens, and computes the proportion of greens in their sample. Which of the following statements is true? |
Multiple Choice:
|
437) Problem #PRAE67T "PRAE67T - 145995 - Records at a larg..." |
Records at a large university (not UCLA, of course) indicate that 20% of all freshmen are placed on academic probation at the end of the first semester. A random sample of 100 freshmen found that 25% of them were placed on probation. The results of the sample: |
Multiple Choice:
|
438) Problem #PRAE6RR "PRAE6RR - 145559 - Zandree is in cha..." |
Zandree is in charge of sampling widgit measurements from a very large population of widgits. lately her standard errors have been alarmingly high for her sample means. If she wants to decrease her sampling error (standard deviation of her sample means) by 1/2 what should she do? |
Multiple Choice:
|
439) Problem #PRAE6RS "PRAE6RS - 145560 - A random sample o..." |
A random sample of 121 students from the UCLA was selected to estimate the average ACT score of all UCLA students. The average for the sample was 23.4 and the sample standard deviation was 3.65. If you wanted to calculate a more precise and accurate prediction of the average ACT score of UCLA students, which one of the following would be the best thing to do? |
Multiple Choice:
|
440) Problem #PRAE7T2 "PRAE7T2 - 146591 - In the context of..." |
A)
In the context of regression analysis , which of the following statements are true? I. A linear transformation increases the linear relationship between variables. II. A logarithmic model is the most effective transformation method to achieve linearity. III. A residual plot reveals departures from linearity. (A) I only (B) II only (C) III only (D) I and II only (E) I, II, and III |
Exact Match (case sensitive):
|
Hints: |
|
B)
In the context of regression analysis , which of the following statements are true? I. When the sum of the residuals is greater than zero, the model is nonlinear. II. Outliers reduce the coefficient of determination. III. Influential points reduce the correlation coefficient. (A) I only (B) II only (C) III only (D) I and II only (E) I, II, and III |
Exact Match (case sensitive):
|
Hints: |
|
C)
A researcher uses a regression equation to predict home heating bills (dollar cost), based on home size (square feet). The correlation between predicted bills and home size is 0.70. What is the correct interpretation of this finding? (A) 70% of the variability in home heating bills can be explained by home size. (B) 49% of the variability in home heating bills can be explained by home size. (C) For each added square foot of home size, heating bills increased by 70 cents. (D) For each added square foot of home size, heating bills increased by 49 cents. (E) None of the above. |
Exact Match (case sensitive):
|
Hints: |
|
441) Problem #PRAE7MD "PRAE7MD - 146385 - A college admissi..." |
A college admissions officer is concerned that their admission criteria might not treat men and women with equal weight. To test this, the college took a random sample of male and female high school seniors from a very large local school district and determined the percent of males and females who would be eligible for admission at the college. Which of the following is a suitable null hypothesis for this test? |
Multiple Choice:
|
442) Problem #PRAE7ME "PRAE7ME - 146386 - The average blood..." |
The average blood pressure for adults in the 30-40 year old age range is about 135. A researcher wonders whether the blood pressure of individuals with high stress positions differs from 135, keeping age range constant. For a random sample of 120 people with high stress jobs, he found: X_bar = 137 p-value = 0.11 95% CI (139 to 141) Based on these findings, he decided not to reject the null. Did he make the right decision? |
Multiple Choice:
|
443) Problem #PRAE7MF "PRAE7MF - 146387 - We want to determ..." |
We want to determine if college GPAs differ for male athletes in major sports (e.g., football), minor sports (e.g., swimming), and intramural sports. What statistical method is most likely to be used to answer this question? Assume that all neccessary assumptions have been met for using this procedure. |
Multiple Choice:
|
444) Problem #PRAE7MG "PRAE7MG - 146388 - In a one-way ANOV..." |
In a one-way ANOVA with 3 groups, a rejection of the null hypothesis implies that: |
Multiple Choice:
|
445) Problem #PRAE7MH "PRAE7MH - 146389 - The journal Pedia..." |
The journal Pediatrics compared the attempted suicide rates between youths who were adopted and those who were not. The null hypothesis is that the rates are the same, and the alternative is that those who were adopted have a higher suicide attempt rate. Which of the following is an example of a Type I error? |
Multiple Choice:
|
446) Problem #PRAE7MJ "PRAE7MJ - 146390 - An after-school p..." |
An after-school program in math is willing to renew its contract with a tutoring agency if the standardized math scores of the students increase by more than 10%. Over the last five years, 2000 students from the after-school program have attended this tutoring agency. In this context, what would happen if the after-school program makes a type II error? |
Multiple Choice:
|
447) Problem #PRAE7MK "PRAE7MK - 146391 - The standard medi..." |
The standard medication for a certain disease is effective in 60% of all cases. A pharmaceutical company believes that its new drug is more effective than the standard treatment. Formulate the null and the alternative hypotheses to test whether there is statistical evidence to support the new drug. |
Multiple Choice:
|
448) Problem #PRAE7MM "PRAE7MM - 146392 - An experiment com..." |
An experiment compares the taste of instant versus fresh-brewed coffee. Each subject tastes two unmarked cups of coffee in random order, one of each type, and states which he or she prefers. Of the 300 subjects who participate in the study, 114 prefer the instant coffee. Is there statistically significant evidence in the sample to support the suspicion that a majority of people prefer the taste of fresh-brewed coffee? Write the null and the alternative hypotheses for this test. |
Multiple Choice:
|
449) Problem #PRAE7MP "PRAE7MP - 146394 - A team of sociolo..." |
A team of sociologists is investigating attitudes towards religion. In particular, they wish to examine differences in attitudes between the genders. They take a random sample of 400 married couples, and ask both people in the couple: "Do you believe in a literal heaven and hell?". About 55% of the women and 54% of the men said that they did believe. The sociologists wish to perform a hypothesis test to test whether the percent of men who believe in a literal heaven and hell in the population is the same as the percent of women. Which of the following statements is true? |
Multiple Choice:
|
450) Problem #PRAE7MQ "PRAE7MQ - 146395 - A company is sued..." |
A company is sued for job discrimination because only 19% of the newly hired candidates were minorites when 27% of all applicants were minorities. The lawyers will perform a hypothesis test to test whether the company's hiring practices are discriminatory. How will the power of the test compare if the test is done at the 5% level of significance as opposed to the 1% level of significance? |
Multiple Choice:
|
451) Problem #PRAE7MR "PRAE7MR - 146396 - A manufacturer of..." |
A manufacturer of automobiles purchases machine bolts from a supplier who claims that no more than 5% of his bolts are defective. The manufacturer suspects that this claim is false. From a random sample of 400 bolts, the manufacturer found that 28 are defective. Is there suficient evidence to reject the supplier's claim? |
Multiple Choice:
|
452) Problem #PRAE7MS "PRAE7MS - 146397 - When a roulette w..." |
When a roulette wheel is perfectly balanced, in the long run red numbers should turn up 18 times in 38 spins. To test its wheel, one casino records the results of 3,800 plays, finding 1,000 red numbers. Based on how a roulette wheel is supposed to work, is that too few reds? Test at the 0.05 level. |
Multiple Choice:
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453) Problem #PRAE7MU "PRAE7MU - 146399 - When you set the ..." |
When you set the significance level for a hypothesis test, what are you controlling for? |
Multiple Choice:
|
454) Problem #PRAE7MV "PRAE7MV - 146400 - When conducting a..." |
When conducting a formal hypothesis test, there are different errors that may be made, depending on your decision. One decision is to reject the null hypothesis. If you falsely reject the null hypothesis, what type of error has been made? |
Multiple Choice:
|
455) Problem #PRAE7C7 "PRAE7C7 - 146162 - Inferences About ..." |
Inferences About Two Means: Dependent Samples Problem 1 If we want to estimate the mean difference in scores on a pre-test and post-test for a sample of students, how should we proceed? |
Multiple Choice:
|
456) Problem #PRAE7DA "PRAE7DA - 146165 - Inferences About ..." |
Inferences About Two Means: Independent Samples Problem 1 A researcher wants to compare all students at Kansas State University (population = 22,000) with all residents of the city of Springfield, IL (population = 22,000). He wants to estimate the average age of each population using two separate samples. He wants the same margin of error for each of his sample means. How would the size of the two samples compare? |
Multiple Choice:
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457) Problem #PRAE7DC "PRAE7DC - 146167 - Inferences About ..." |
Inferences About Two Means: Independent Samples Problem 2 For this research situation, decide what statistical procedure would most likely be used to answer the research question posed. Assume all assumptions have been met for using this procedure. Does knowing a college student's SAT score tell us anything about his or her first year college grade point average? |
Multiple Choice:
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458) Problem #PRAE7DD "PRAE7DD - 146168 - Inferences About ..." |
Inferences About Two Means: Independent Samples Problem 3 Suppose you were hired to conduct a study to find out which of two brands of soda college students think taste better. In your study, students are given a blind taste test. They rate one brand and then rate the other, in random order. The ratings are given on a scale of 1 (awful) to 5 (delicious). Which type of test would be the best to compare these ratings? |
Multiple Choice:
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459) Problem #PRAE7DF "PRAE7DF - 146170 - Inferences About ..." |
Inferences About Two Means: Independent Samples Problem 4 In a study of graduate students who took the Graduate Record Exam (GRE), the Educational Testing Service reported that for the quantitative exam, U.S. citizens had a mean of 529 and a standard deviation of 127, whereas the non-U.S. citizens had a mean of 649 and a standard deviation of 129. Choose the best answer from the following. |
Multiple Choice:
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460) Problem #PRAE7DH "PRAE7DH - 146172 - Inferences About ..." |
Inferences About Two Proportions Problem 1 A random sample of 1000 Americans aged 65 and older was collected in 1980 and found that 15% had "hazardous" levels of drinking, which is defined as regularly drinking an amount of alcohol that could cause health problems given the subject's medical conditions. Researchers wanted to know if this proportion has changed since 1980 and so collected a random sample of 1500 Americans aged 65 and older in 2004. They found that 12% drank at hazardous levels. Which of the following is closest to the value of a test statistic that could be used to test the hypothesis that the proportion of hazardous drinkers over the age of 65 has declined since 1980? |
Multiple Choice:
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461) Problem #PRASGT "PRASGT - 2003retest_5_gr10 (2006/11/05 15:15:40)" |
Corey has a part-time job cleaning rooms at a hotel. He is paid $6.75 an hour. If it takes him approximately 22 minutes to clean one room, which of the following is closest to the amount he is being paid to clean one room? |
Multiple Choice:
|
Scaffold:
|
Scaffold:
|
462) Problem #PRAE7KH "PRAE7KH - 146358 - X N (60, 9). Su..." |
A)
X N (60, 9). Suppose that you form random samples of 25 from this distribution. Let X be the random variable of averages. Let ∑X be the random variable of sums. For c - f, sketch the graph, shade the region, label and scale the horizontal axis for X, and find the probability. Sketch the distributions of X and X on the same graph. Sketches should be completed in your notebook. |
Multiple Choice:
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B)
X ~ |
Algebraic Expression:
|
C)
P (X < 60) = |
Algebraic Expression:
|
D)
Find the 30th percentile. |
Algebraic Expression:
|
E)
P (56 < X < 62)= Round to the nearest hundreth. |
Algebraic Expression:
|
F)
P(18 < X < 58)= |
Algebraic Expression:
|
G)
∑X~ Round to the nearest hundreth. |
Algebraic Expression:
|
H)
Find the minimum value for the upper quartile. Round to the nearest hundreth. |
Algebraic Expression:
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463) Problem #PRAE7AF "PRAE7AF - 146077 - Hong is a pharmac..." |
Hong is a pharmacist studying the effect of an anti-depressant drug. She organizes a simple random sample of 100 patients, and then collect their anxiety test scores before and after administering the anti-depressant drug. Hong wants to estimate the mean difference between the pre-drug and post-drug test scores. How should she proceed? |
Algebraic Expression:
|
464) Problem #PRAE7AG "PRAE7AG - 146078 - A utility company..." |
A utility company serves 50,000 households. As part of a survey of customer attitudes, they take a simple random sample of 750 of these households. The average number of television sets in the sample households turns out to be 1.86, and the standard deviation in the sample is 0.80. What sample size would be necessary for the standard error of the sample mean to be 0.02? |
Algebraic Expression:
|
465) Problem #PRAE7AH "PRAE7AH - 146079 - Statistics show t..." |
Statistics show that the average level of a mother's education for a city of 300,000 people is 14 years with a standard deviation of 1.5 years. A major state university is located in this town. The administrators in this university think that the average level of a mother's education for the freshmen who are admitted to this school is higher than 14 years. The average education level of mothers for a random sample of 100 freshmen who were admitted to this university within the last two years was 14.7 years. We want to test the null at the level of alpha = 0.001. What is the best answer? |
Algebraic Expression:
|
466) Problem #PRAE7AJ "PRAE7AJ - 146080 - A class of 50 eig..." |
A class of 50 eighth-graders took a standardized reading test. Their scores had a mean of 107.5 and a standard deviation of 10.5. The national mean score on the test is 100. The probability of observing an x-bar as large or larger than 100 if the null hypothesis is true is |
Algebraic Expression:
|
467) Problem #PRAE7AK "PRAE7AK - 146081 - To test the claim..." |
To test the claim that the average home in a certain town is within 5.5 miles of the nearest fire station, and insurance company measured the distances from 25 randomly selected homes to the nearest fire station and found x-bar = 5.8 miles and sd = 2.4 miles. Determine what the insurance company found out with a test of significance. Check all that apply. |
Check All That Apply:
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468) Problem #PRAE7AM "PRAE7AM - 146082 - For mothers who a..." |
For mothers who are between 20 and 40 years old and who gain between 20 and 35 during the course of their pregnancies, the average birth weight of their babies is 7.0 pounds and the standard deviation is 0.85 pounds. Researchers want to determine if mothers who are also between 20 and 40 years old but who gained less than 20 pounds during the course of their pregnancies will have babies that have different birth weights. The average weight of babies born to a random sample of 64 mothers who had gained between 10-18 pounds during the course of their pregnancy was 6.83 pounds. Should we accept or fail to reject the null hypothesis and why? |
Algebraic Expression:
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469) Problem #PRAE7AN "PRAE7AN - 146083 - The average lengt..." |
The average length of time required to complete a certain aptitude test is claimed to be 80 minutes. A random sample of 25 students yielded an average of 86.5 minutes and a standard deviation of 15.4 minutes. If we assume normality of the population distribution, is there evidence to reject the claim? |
Check All That Apply:
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470) Problem #PRAE7AP "PRAE7AP - 146084 - A random sample o..." |
A random sample of 1000 Americans aged 65 and older was collected in 1980 and found that 15% had "hazardous" levels of drinking, which is defined as regularly drinking an amount of alcohol that could cause health problems given the subject's medical conditions. Researchers wanted to know if this proportion has changed since 1980 and so collected a random sample of 1500 Americans aged 65 and older in 2004. They found that 12% drank at hazardous levels. Which of the following is closest to the value of a test statistic that could be used to test the hypothesis that the proportion of hazardous drinkers over the age of 65 has declined since 1980? |
Algebraic Expression:
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471) Problem #PRAE7AQ "PRAE7AQ - 146085 - Based on past exp..." |
Based on past experience, a bank believes that 4% of the people who receive loans will not make payments on time. The bank has recently approved 300 loans. What is the probability that over 6% of these clients will not make timely payments? |
Algebraic Expression:
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472) Problem #PRAE7AR "PRAE7AR - 146086 - A marketing direc..." |
A marketing director for a radio station collects a random sample of three hundred 18 to 25 year-olds and two hundred and fifty 25 to 40 year-olds. She records the percent of each group that had purchased music online in the last 30 days. She performs a hypothesis test, and the p-value of her test turns out to be 0.15. From this she should conclude: |
Algebraic Expression:
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473) Problem #PRAE7AS "PRAE7AS - 146087 - Problem #146087" |
Algebraic Expression:
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474) Problem #PRAE7AT "PRAE7AT - 146088 - Many people sleep..." |
Many people sleep in on the weekends to make up for short nights during the work week. The Better Sleep Council reports that 61% of us get more than 7 hours of sleep per night on the weekend. A random sample of 350 adults found that 235 had more than seven hours each night last weekend. At the 0.05 level of significance, does this evidence show that more than 61% of us get seven or more hours off sleep per night on the weekend? |
Algebraic Expression:
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475) Problem #PRAE7AU "PRAE7AU - 146089 - John has just sta..." |
John has just started a tutoring agency. He decides to to take a risk and place a large ad in the Sunday issue of the L.A. Times and hopes that the name recognition is worth the high cost of the ad. He hopes that at least 40% of the neighborhood will recognize the ad. On Monday he contacts 125 randomly selected households who receive the LA Times and he finds that 56 of them had noticed the ad. Would you recommend that John continue to place the ad in the Sunday edition of the L.A. Times? |
Algebraic Expression:
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476) Problem #PRAE8R2 "PRAE8R2 - 147490 - Suppose that the ..." |
A)
Suppose that the length of research papers is uniformly distributed from 10 to 25 pages. We survey a class in which 55 research papers were turned in to a professor. We are interested in the average length of the research papers.
a. In words, X = |
Algebraic Expression: |
B)
b. X~ |
Algebraic Expression:
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C)
c. mX = |
Algebraic Expression:
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D)
d. sX = |
Algebraic Expression:
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E)
e. In words, X = |
Algebraic Expression: |
F)
f. X~ |
Algebraic Expression:
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G)
g. In words, SX = |
Algebraic Expression: |
H)
h. SX~ |
Algebraic Expression:
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I)
i. Without doing any calculations, do you think that it's likely that the professor will need to read a total of more than 1050 pages? Why? |
Algebraic Expression: |
J)
j. Calculate the probability that the professor will need to read a total of more than 1050 pages. |
Algebraic Expression:
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K)
k. Why is it so unlikely that the average length of the papers will be less than 12 pages? |
Algebraic Expression: |
477) Problem #PRAE8SB "PRAE8SB - 147499 - The length of son..." |
A)
The length of songs in a collector's CD collection is uniformly distributed from 2 to 3.5 minutes. Suppose we randomly pick 5 CDs from the collection. There is a total of 43 songs on the 5 CDs. a. In words, X = |
Algebraic Expression: |
B)
b. X~ |
Algebraic Expression: |
C)
c. In words, X= |
Algebraic Expression: |
D)
d. X~ |
Algebraic Expression: |
E)
e. Find the first quartile for the average song length. |
Algebraic Expression: |
F)
f. The IQR (interquartile range) for the average song length is from _______ to _______. |
Algebraic Expression: |
478) Problem #PRAE8SE "PRAE8SE - 147502 - Salaries for teac..." |
A)
Salaries for teachers in a particular elementary school district are normally distributed with a mean of $44,000 and a standard deviation of $6500. We randomly survey 10 teachers from that district.
a. In words, X = |
Algebraic Expression: |
B)
b. In words, X = |
Algebraic Expression: |
C)
c. X~ |
Algebraic Expression: |
D)
d. In words, SX = |
Algebraic Expression: |
E)
e. SX~ |
Algebraic Expression: |
F)
f. Find the probability that the teachers earn a total of over $400,000. |
Algebraic Expression: |
G)
g. Find the 90th percentile for an individual teacher's salary. |
Algebraic Expression: |
H)
h. Find the 90th percentile for the average teachers' salary. |
Algebraic Expression: |
I)
i. If we surveyed 70 teachers instead of 10, graphically, how would that change the distribution for X? |
Algebraic Expression: |
J)
j. If each of the 70 teachers received a $3000 raise, graphically, how would that change the distribution for X? |
Algebraic Expression: |
479) Problem #PRAE8SN "PRAE8SN - 147509 - The distribution..." |
A)
The distribution of income in some Third World countries is considered wedge shaped (many very poor people, very few middle income people, and few to many wealthy people). Suppose we pick a country with a wedge distribution. Let the average salary be $2000 per year with a standard deviation of $8000. We randomly survey 1000 residents of that country. a. In words, X = |
Algebraic Expression: |
B)
b. In words, X = |
Algebraic Expression: |
C)
c. X~ |
Algebraic Expression: |
D)
d. How is it possible for the standard deviation to be greater than the average? |
Algebraic Expression: |
E)
e. Why is it more likely that the average of the 1000 residents will be from $2000 to $2100 than from $2100 to $2200? |
Algebraic Expression: |
480) Problem #PRAE8SP "PRAE8SP - 147510 - The average leng..." |
A)
The average length of a maternity stay in a U.S. hospital is said to be 2.4 days with a standard deviation of 0.9 days. We randomly survey 80 women who recently bore children in a U.S. hospital. a. In words, X = |
Algebraic Expression: |
B)
b. In words, X = |
Algebraic Expression: |
C)
c. X~ |
Algebraic Expression: |
D)
d. In words, SX = |
Algebraic Expression: |
E)
e. SX~ |
Algebraic Expression: |
F)
f. Is it likely that an individual stayed more than 5 days in the hospital? Why or why not? |
Algebraic Expression: |
G)
g. Is it likely that the average stay for the 80 women was more than 5 days? Why or why not? |
Algebraic Expression: |
H)
h. Which is more likely: i. an individual stayed more than 5 days; or ii. the average stay of 80 women was more than 5 days? i. If we were to sum up the women's stays, is it likely that, collectively they spent more than a year in the hospital? Why or why not? |
Algebraic Expression: |
481) Problem #PRAE8SQ "PRAE8SQ - 147511 - In 1940 the avera..." |
A)
In 1940 the average size of a U.S. farm was 174 acres. Let's say that the standard deviation was 55acres. Suppose we randomly survey 38 farmers from 1940. (Source: U.S. Dept. of Agriculture) a. In words, X = |
Algebraic Expression: |
B)
b. In words, X = |
Algebraic Expression: |
C)
c. X~ |
Algebraic Expression: |
D)
d. The IQR for X is from _______ acres to _______ acres. |
Algebraic Expression: |
482) Problem #PRAE8SR "PRAE8SR - 147512 - The stock closing..." |
A)
The stock closing prices of 35 U.S. semiconductor manufacturers are given below. (Source: Wall Street Journal) 8.625; 30.25; 27.625; 46.75; 32.875; 18.25; 5; 0.125; 2.9375; 6.875; 28.25; 24.25; 21; 1.5; 30.25; 71; 43.5; 49.25; 2.5625; 31; 16.5; 9.5; 18.5; 18; 9; 10.5; 16.625; 1.25; 18; 12.875; 7; 12.875; 2.875; 60.25; 29.25
a. In words, X = |
Algebraic Expression: |
B)
b. i. x = ii. sx = iii. n = |
Algebraic Expression: |
C) |
Algebraic Expression: |
D)
d. In words, describe the distribution of stock prices. |
Algebraic Expression: |
E)
e.Randomly average 5 stock prices together. (Use a random number generator.) Continue averaging widths of 10. |
Algebraic Expression: |
F)
f. Use the 10 averages from (e) to calculate: i. x = ii. sx = |
Algebraic Expression: |
G) |
Algebraic Expression: |
H)
h. Does this histogram look like the graph in (c)? |
Algebraic Expression: |
I)
i. In 1 - 2 complete sentences, explain why the graphs either look the same or look different? |
Algebraic Expression: |
J)
j. Based upon the theory of the Central Limit Theorem, X~ |
Algebraic Expression: |
483) Problem #PRAE8SS "PRAE8SS - 147513 - The time to wait ..." |
The time to wait for a particular rural bus is distributed uniformly from 0 to 75 minutes. 100 riders are randomly sampled to learn how long they waited. The 90th percentile sample average wait time (in minutes) for a sample of 100 riders is: |
Multiple Choice:
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484) Problem #PRAE8SU "PRAE8SU - 147515 - The time to wait ..." |
The time to wait for a particular rural bus is distributed uniformly from 0 to 75 minutes. 100 riders are randomly sampled to learn how long they waited. Would you be surprised, based upon numerical calculations, if the sample average wait time (in minutes) for 100 riders was less than 30 minutes? |
Multiple Choice:
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485) Problem #PRAE8SV "PRAE8SV - 147516 - Which of the foll..." |
Which of the following is NOT TRUE about the distribution for averages? |
Multiple Choice:
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486) Problem #PRAE8SW "PRAE8SW - 147517 - The cost of unlea..." |
The cost of unleaded gasoline in the Bay Area once followed an unknown distribution with a mean of $2.59 and a standard deviation of $0.10. Sixteen gas stations from the Bay Area are randomly chosen. We are interested in the average cost of gasoline for the 16 gas stations. What is the probability that the average price for 16 gas stations is over $2.69? A. Almost zero B. 0.1587 C. 0.0943 |
Algebraic Expression:
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487) Problem #PRAE8SY "PRAE8SY - 147519 - For the Charter S..." |
A)
For the Charter School Problem (Example 3) in Central Limit Theorem: Using the Central Limit Theorem, calculate the following using the normal approximation to the binomial.
A. Find the probability that less than 100 favor a charter school for grades K - 5. |
Algebraic Expression: |
B)
B. Find the probability that 170 or more favor a charter school for grades K - 5. |
Algebraic Expression: |
C)
C. Find the probability that no more than 140 favor a charter school for grades K - 5. |
Algebraic Expression: |
D)
D. Find the probability that there are fewer than 130 that favor a charter school for grades K - 5. |
Algebraic Expression: |
E)
E. Find the probability that exactly 150 favor a charter school for grades K - 5. |
Algebraic Expression: |
488) Problem #PRAE8SZ "PRAE8SZ - 147520 - Four friends, Jan..." |
A)
Four friends, Janice, Barbara, Kathy and Roberta, decided to carpool together to get to school. Each day the driver would be chosen by randomly selecting one of the four names. They carpool to school for 96 days. Use the normal approximation to the binomial to calculate the following probabilities. A. Find the probability that Janice is the driver at most 20 days. |
Algebraic Expression: |
B)
B. Find the probability that Roberta is the driver more than 16 days. |
Algebraic Expression: |
C)
C. Find the probability that Barbara drives exactly 24 of those 96 days. |
Algebraic Expression: |
489) Problem #PRAE7Y9 "PRAE7Y9 - 146753 - This problem sho..." |
This problem should be completed in your notebook. After you are done, click on "I have completed the answer in my notebook" and submit answer. |
Multiple Choice:
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490) Problem #PRAE7ZP "PRAE7ZP - 146766 - This problem sho..." |
This problem should be done in your notebook. After you are done, click on "I have completed the answer in my notebook" and submit answer. |
Multiple Choice:
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491) Problem #PRAE7ZS "PRAE7ZS - 146769 - This problem sho..." |
This problem should be done in you notebook. After you are done, click "I have completed the answer in my notebook" and submit answer. |
Multiple Choice:
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492) Problem #PRAE8K3 "PRAE8K3 - 147336 - A soccer coach se..." |
A)
A soccer coach selects 6 players from a group of boys aged 8 to 10, 7 players from a group of boys aged 11 to 12, and 3 players from a group of boys aged 13 to 14 to form a recreational |
Multiple Choice:
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B)
A pollster interviews all human resource personnel in five different high tech companies. |
Multiple Choice:
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C)
An engineering researcher interviews 50 women engineers and 50 men engineers. |
Algebraic Expression:
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D) |
Algebraic Expression:
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493) Problem #PRAE8ST "PRAE8ST - 147514 - An experiment co..." |
A)
An experiment consists of tossing two 12 sided dice (the numbers 1-12 are printed on the sides of the dice). Let Event A= both die show an even number Let Event B= both die show a number more than 8 Events A and B are: |
Multiple Choice:
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B)
Find P (A|B) as a fraction: |
Multiple Choice:
|
C)
Which of the following are TRUE when we perform a hypothesis test on matched or paired samples? |
Multiple Choice:
|
D)
118 students were asked what type of color
their bedrooms were painted: light colors, dark colors or vibrant
colors. The results were tabulated according to gender. Light colors Dark colors Vibrant colors Female 20 22 28 Male 10 30 8 Find the probability that a randomly chosen student is male or has a bedroom painted with light colors. |
Multiple Choice:
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E)
Find the probability that a randomly chosen student is male given the student's bedroom is painted with dark colors. |
Multiple Choice:
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494) Problem #PRAE8S5 "PRAE8S5 - 147524 - We are interested..." |
A)
We are interested in the number of times a teenager must be reminded to do his/her chores each week. A survey of 40 mothers was conducted. The table shows the results of the survey. Find the probability that a teenager is reminded 2 times.
|
Multiple Choice:
|
B)
Find the expected number of times a teenager is reminded to do his/her chores. |
Multiple Choice:
|
C)
On any given day, approximately 37.5% of the cars parked in the De Anza parking structure are parked crookedly. We randomly survey 22 cars. We are interested in the number of cars parked crookedly. For every 22 cars, how many would you expect to be parked crookedly, on average? Round to the nearest car! |
Multiple Choice:
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D) |
Multiple Choice:
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495) Problem #PRAE8S4 "PRAE8S4 - 147523 - The following adu..." |
A)
The following adult ski sweater prices are from the Gorsuch Ltd. Winter catalog: {$212, $292, $199, $280, $236} Assume the underlying sweater price population is approximately normal. The null hypothesis is that the average price of adult ski sweaters from Gorsuch Ltd. is at least $275. The correct distribution to test this hypothesis is: |
Multiple Choice:
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B)
The hypothesis test: |
Multiple Choice:
|
C)
A clothing store would use which measure of the center of data when placing orders? |
Multiple Choice:
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496) Problem #PRAE8S6 "PRAE8S6 - 147525 - According to a Fi..." |
A)
According to a Field Poll conducted February 8-17, 2005, 79% of California adults (400 out of 506) feel that "education and our schools" is one of the top issues facing California. We wish to construct a 90% confidence interval for the true proportion of California adults who feel that education and the schools is one of the top issues facing California. A point estimate for the true population portion is: |
Multiple Choice:
|
B)
A 90% confidence interval for the population proportion is: |
Multiple Choice:
|