Question

Two college instructors are interested in whether or not there is any variation in the way they grade math exams. They each grade the same set of 12 exams. The first instructor's grades have a variance of 52.3. The second instructor's grades have a variance of 89.9. Test the claim that the first instructor's variance is smaller. The level of significance is 5%.

Answer 1

## It is two sample variance test :

one tailed left tailed test :

F statistics = 0.5817

F critical value = here test is left tailed test hence critical value is lower tailed = 0.355

here we fail to reject Ho because F statistics > F critical value .

and conclusion our claim is not satisfy .