Do students who register for early morning classes typically do better than those who sign up for later day classes? Random samples from two elementary statistics classes were taken to determine if a significant difference exists in the variability and means of grades for a probability test given to both classes.

a. Are the assumptions of normality satisfied? Explain.
b. Is there sufficient evidence to reject the hypothesis of equal variances of grades for these two classes? Use a = 0.05
c. Is there sufficient evidence to reject the hypothesis that there is no difference between the mean probability test grades for these two classes? Use a = 0.05

Early morning grades 78 92 86 78 89 100 97 53 86 58 78 100 92 83 Later day grades 89 100 92 78 100 67 58 100 78 100 89 83