1) Problem #PRAJBJ2 "PRAJBJ2 - Oprah's Book Club" |
Oprah’s book club is having a meeting. There are six women in the room already, ages 33, 34 and 35. There are two woman of each age in the room. If two women, both aged 34 enter the room. © STATS4STEM.ORG |
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2) Problem #PRAJBNX "PRAJBNX - 239650 - The average numbe..." |
The average number of calories consumed per day is 2000. The distribution is normal and 68% lies in the middle of the distribution between 1850 and 2150. What is the notation for this distribution? © STATS4STEM.ORG |
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3) Problem #PRAJ92E "PRAJ92E - 267875 - In this problem w..." |
A)
In this problem we wish to model the relationship between age and percentage of body fat. The data comes from the agefat dataset that provides the results of a study investigating a new methods of measuring body composition (see Mazess et al, 1984), and give the body fat percentage (percent fat), age and sex for 25 normal adults aged between 23 and 61 years. The questions of interest are how are age and percent fat related. A summary of the linear regression output is provided below: What is the explanatory variable in this analysis? © STATS4STEM.ORG |
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B)
What is the sample size for this dataset? |
C)
What is the number of the point estimate that represent the average increase in the percenatage of body fat for every incease in age of 1 year? Round answer to the nearest hundredth. |
D)
For inference pertaining to linear regression, the following four conditions must be checked before drawing any valid conclusions. A) True linear relationship between explanatory and response variables. B) Constant variance of residuals. C) Independent observations. D) Residuals are normally distributed. Using the graphics provided below, which of the above conditions appear to be met? Check ALL that appy. |
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E)
You wish to conduct the following hypothesis test for beta: For such a test, what formula would you use to calculate the test statistic? A) B) C) D) E) None of the above |
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F)
What is the SEb? Round answer to the nearest hundredth. |
G)
Calculate the test statistic for this test. Round answer to the nearest hundredth. |
I)
Is the following statement correct? The p-value we calculated is less than 0.0005. Therefore, we reject the null hypothesis. The data fails to support the claim that the beta, the true slope of the least squares regression line, is greater than 0. Hint - Read question carefully. |
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4) Problem #PRAKCGE "PRAKCGE - 270231 - Which equation is..." |
A)
Which equation is used to model exponential growth? A) y-hat = a + bx B) log(y-hat) = a + bx C) y-hat = a + b*log(x) D) log(y-hat) = a + b*log(x) © STATS4STEM.ORG |
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B)
Which equation is used to model the power law? A) y-hat = a + bx B) log(y-hat) = a + bx C) y-hat = a + b*log(x) D) log(y-hat) = a + b*log(x) |
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5) Problem #PRAJBZQ "PRAJBZQ - 239984 - There are 30 stud..." |
There are 30 students in a math class. 75% of the students completed their homework. If the teacher randomly checks 20 students’ homework, what is the probability that at least 15 of them completed the homework assignment? Round answer to the nearest hundredth. © STATS4STEM.ORG |
6) Problem #PRAE8Z8 "PRAE8Z8 - 147744 - Which statement i..." |
Which statement is correct? © STATS4STEM.ORG |
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7) Problem #PRAJEZR "PRAJEZR - 237863 - Hypothesis Test - 1 Sample Mean - EJS" |
A)
A laptop advertises that the average battery life is 12 hours. A consumer group tests to see if the average battery life is actually less than the stated battery life. It is known that the the distribution for the battery life of individual laptops is normal with a standard deviation of 2.3 hours. The consumer group randomly samples 36 laptops and they record the battery life of each laptop. The sample mean is calculated to be 11.44 hours.
For this problem, what would be considered the null and alternative hypothesis?A) H0: μ > 12 HA: μ < 12 B) H0: μ = 12 HA: μ < 12 C) H0: x-bar = 11.44 HA: x-bar ≠ 11.44 D) H0: x-bar = 12 HA: x-bar < 12 E) Ho: μ = 11.44 HA: μ < 11.44 F) H0: μ ≠ 12 HA: μ < 12 G) Ho: μ > 11.44 HA: μ < 11.44 © STATS4STEM.ORG |
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B)
For this hypothesis test, the sample mean was calculated as 11.44 hours and the null and alternative hypothesis are: HO: μ = 12 HA: μ < 12 If we assume that the null is true, what is the mean of the sampling distribution for x-bar? |
C)
If we assume that the null is true, what is the standard deviation of the sampling distribution for x-bar? Round answer to the nearest hundredth. |
D)
What is the p-value for this problem? Round answer to the nearest hundredth. |
E)
If we assume the level of significance is 0.05, we can: |
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F)
If we assume the level of significance is 0.10, we can:
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G)
Calculate the margin of error for a confidence interval with a confidence level of 99%. Round answer to the nearest hundredth. Link to t-table |
8) Problem #PRAJVGM "PRAJVGM - 255822 - Read/Refer to thi..." |
A)
Read/Refer to this chi-square test webpage to answer the following questions. The ________________________is a way of determining whether a set of categorical data came from a claimed discrete distribution or not. The null hypothesis is that they did and the alternate hypothesis is that they didn't. © STATS4STEM.ORG |
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B)
True or False? As with all other tests, certain conditions must be checked before a chi-square test of anything is carried out. |
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C)
True or False: The process for calculating the p-value for test of homogeneity and test of independence are the same. |
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D)
True or False: For a goodness-of-fit test, the degrees of freedom = (r-1)(c-1) |
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E)
True or False: If you're thinking, "homogeneity and independence sound the same!", you're nearly right. The difference is a matter of design. In a test of independence, observational units are collected at random from one population only, whereas for the the test of homogeneity, the data are collected by randomly sampling from each sub-group separately. (Say, 100 blacks, 100 whites, 100 American Indians, and so on.). |
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9) Problem #PRAKM5X "PRAKM5X - 278555 - An oil company is..." |
A)
An oil company is running an experiment to determine how little they have to refine the oil before cars start performing poorly. The company is planning to use oil that is refined at the following levels: 80%, 85%, 90%, 95%, and 100%. The study will use 50 cars, so 10 cars will be used for each percentage of refination. The researchers will fill up each car with the same amount of fuel and then test the efficiency of the engine, in miles per gallon, over a set distance. All the cars used are the same model and in the same condition. a) What are the experimental units for this experiment? © STATS4STEM.ORG |
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B)
b) What are the treatments for this experiment? |
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C)
c) What is the response variable for this experiment? |
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