1) College admissions administrators at a university are reevaluating their entrance requirements. They believe that the mean GPA for graduating high school seniors has increased dramatically over the last decade. They randomly sample 85 records of graduating seniors from 10 years ago (sample 1) and find an average GPA of 2.68. An independent random sample of 80 current graduating seniors yields an average GPA of 2.94. If the population variance of high school GPA is 0.2601, find a 95% confidence interval for the difference in population mean GPA over the last decade. a. (-0.46, -0.05) b. (-0.36, -0.16) C. (-0.29, -0.13) d. (-0.42, -0.10) 2). Price gouging occurs when retailers use the unfortunate circumstances of others to charge exorbitant prices for needed products. This frequently occurs after a significant natural disaster. Suppose an area experiences a devastating hurricane and authorities suspect price gouging occurred. The average price for a gallon of milk in the area was $2.34 prior to the hurricane. If after the hurricane we sample 10 stores and find the average price is now $3.05 with a standard deviation of 98 cents, does it appear the average price of milk increased significantly after the hurricane? State the critical value (CV), test statistic (TS), and decision from the test. (Use a = 0.05.) a. CV = 2.262, TS = 0.72, fail to reject HO b. CV=-1.833, TS = 2.29, fail to reject HO C. CV= -2.262, TS = -0.72, fail to reject HO D CV= 1.833, TS = 2.29, reject HO 3) A psychologist is studying the effect of belly stars on Sneetches. A random sample of four Sneetches is drawn and a test of self-image is given to each Sneetch before and after having their belly star status changed. (If the Sneetch initially had a star, it was removed; if they did not have a star, one was created on them using the patented "Star-off/Star-on" procedure.) The data is collected below: Sneetch #. 1. 2. 3. 4 Image score before. 120 88. 100 25 Image score after. 130 100 110. 55 Does it appear that changing belly star status increases the average self-image of Sneetches? Select the appropriate critical value (CV), test statistic (TS), and decision below. (Use a = 0.10.) a. CV = 1.638, TS = -6.38, fail to reject Ho b. CV =-1.638, TS = -3.19, reject Ho C. CV=-1.533, TS = -3.19, reject Ho d. CV = 1.638, TS = 3.19, reject Ho 4) In a one-way ANOVA, if the null hypothesis is HO: u1 = u2 = 43 = u4, then the alternative hypothesis is: a. Ha: at least two of the population means differ. b. Ha: u1 u2 u3 u4 c. Ha: at least one of the population means differ. d. Ha: none of the population means differ