Two accounting professors decided to compare the variance of their grading procedures. To accomplish this, they each graded the same 10 exams, with the following results:

Mean Grade Standard Deviation
Professor 1 79.3 23.1
Professor 2 82.1 12.7
The calculated F ratio is ________.

Select one:
a. 5.18
b. 3.31
c. 1.78
d. 3.01