Two economics professors decided to compare the variance of their grading procedures. They assume that the variance of the two groups are the same (null hypothesis).To accomplish this, they each graded the same 30 exams, with the following results: (assume that =0.01)

Mean Grade Standard Deviation

Professor 1 65 42

Professor 2 50 25

Select one:

a. Reject the null hypothesis and conclude the variances are different.

b. Fail to reject the null hypothesis and conclude the variances are different.

c. Reject the null hypothesis and conclude the variances are the same.

d. Fail to reject the null hypothesis and conclude the variances are the same.