For Exercises 57 and 58, assume that the given standard deviations are population standard deviations.
57. Use a test to test whether the population mean student ratings differ, using level of significance . Compare your results to Exercises 53 and 55.
10.2.57
. Reject if the . . . The is , so we reject . There is evidence at level of significance that the population mean student evaluation rating for the charismatic group differs from that of the punitive group. The value of in this problem equals the value of in Problem 53 but it is a little bit smaller than the value of in Problem 55 (b). The is smaller than the other s. All three hypothesis tests have the same conclusion of reject .