Homework SourseTwo accounting professors decided to compare the variance of
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:
At the 1% level of significance, what is the decision?
| Mean Grade | Standard Deviation | |
| Professor 1 | 79.3 | 22.4 |
| Professor 2 | 82.1 | 12.0 |
Solution
As
F = s1^2 /s^2 = 22.4^2/12.0^2 = 3.4844
As
df1 = df2 = 10 - 1 = 9, then we see that (from table/technology),
Fcrit = 6.541089627
As F < Fcrit, then we FAIL TO REJECT THE NULL HYPOTHESIS.
We have insufficient evidence to say that there is a difference between the variances of their grading procedures.
