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**Unformatted text preview: **STA 3024 Exam 3 Sample Questions 1. In simple linear regression for a particular data set with 20 observations, suppose we fail to reject H in the regression F test using α = 0 . 05 . Which of the following could be the value of the test statistic in the two-sided regression t test? (A)- 6 . 25 (B)- 3 . 35 (C)- 2 . 68 (D)- 2 . 49 (E)- 1 . 86 2. Suppose we want to use simple linear regression to see how students’ grades on a multiple-choice exam ( Y ) depend on how many hours they study ( X ). We think that students who study less will probably do worse on the exam. We also think that students who study very little will make a lot of guesses on the exam, so there will probably be more variability in their grades than in the grades of people who study more. Which assumption for inference with regression is most likely to be violated in this situation? (A) linearity (B) independence of the observations (C) randomization (D) constant standard deviation (E) normality 3. Suppose that a simple linear regression F test with α = 0 . 05 yields a p-value of 0.33. Which of the following should we do? (A) reject H (B) conclude that it’s reasonable that Y and X are independent (C) both (A) and (B) (D) neither (A) nor (B) 4. In simple linear regression, SS Regr measures the variability of (A) the predicted Y values around the mean of the Y values. (B) the X values around the mean of the Y values. (C) the Y values around the mean of the X values. (D) the Y values around the predicted Y values. (E) the X values around the Y values. 5. Scatterplots of four data sets with the same number of observations are shown below. ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 55 65 75 85 25 30 35 40 X Y Data Set A ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 5.5 6.5 7.5 8.5 25 30 35 40 X Y Data Set B ● ●● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● 55 65 75 85 25 30 35 40 X Y Data Set C ● ●● ● ● ● ● ● ● ● ● ● ● ●...

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