An F-test for equality of variances gives a p-value of .003. At α = .05, what conclusion can be made about the preferred test to compare the means for the same sample?
A)We would prefer a pooled variance t-test for equality of means.
B)We would not wish to pool the variances in a t-test for equality of means.
C)We would prefer a paired t-test for equality of means.
D)The variances have nothing to do with the t-test for equality of means.

Question

Quizplus · Accepted Answer

The significant F-test for equality of variances indicates that the assumption of equal variances for a pooled variance t-test may not be valid. Therefore, in this case, it would be preferable not to pool the variances in a t-test for equality of means. Choosing option A is not appropriate because we cannot use a pooled variance t-test if the assumption of equal variances is not met. Option C suggests a paired t-test, which is only suitable if the data are paired, which is not mentioned in the question. Option D is incorrect because the variance of the two groups can greatly impact the t-test for equality of means through its effect on the standard error.

An F-Test for Equality of Variances Gives a P-Value of .003