4 Do students reduce study time in classes where they achieve a higher midterm score? In a Journal of Economic Education article (Winter 2005), Gregory Krohn and Catherine O'Connor studied student effort and performance in a class over a semester. In an intermediate macroeconomics course, they found that "students respond to higher midterm scores by reducing the number of hours 2 they subsequently allocate to studying for the course." Suppose that a random sample of n = 8 students who performed well on the points midterm exam was taken and weekly study times before and after the exam were compared. The resulting data are given in Table 11.5. Assume that the population of all possible paired differences is normally distributed. Table 11.5 Weekly Study Time Data for Students Who Perform Well on the MidTerm Students 1 2 3 4 5 6 7 8 Before 11 12 16 14 15 19 16 18 After 11 5 8 10 9 9 8 2 Paired T-Test and Cl: StudyBefore, StudyAfter Paired T for StudyBefore - StudyAfter N Mean StDev SE Mean StudyBefore 8 15. 1250 2. 7484 . 9717 StudyAfter 7.7500 2.9155 1. 0308 Difference 7.37500 4. 62717 1. 63595 95% CI for mean difference: (3.50659, 11.24341) T-Test of mean difference = 0 (vs not = 0): T-Value = 4.51, P-Value = .0028 (a) Set up the null and alternative hypotheses to test whether there is a difference in the true mean study time before and after the milterm avam4 Difference 8 7.37588 4.52717 1.53595 95% CI for mean difference: (3.50659. 11.24341) TeTest of mean difference : 0 (vs not: 0): TrValue : 4.51, P7Value : .0028 point5 (a) Set up the null and alternative hypotheses to test whether there is a difference in the true mean study time before and after the midterm exam. H0: ud : versus Ha: pd # (b) Above we present the MINITAB output for the paired differences test. Use the output and critical values to test the hypotheses at the .10, .05, and .01 level of significance. Has the true mean study time changed? (Round your answer to 2 decimal places.) 9 Answer is not complete. [2 , We have lvery strong a levidenoe