Which of the following statements regarding the equal-standard-deviations assumption of the pooled t-test is the most accurate?
A)The pooled t-test is robust to moderate violations of the assumption provided the sample sizes are large.
B)The pooled t-test is robust to moderate violations of the assumption provided the sample sizes are roughly equal.
C)The pooled t-test is robust to moderate violations of the assumption regardless of the sample sizes.
D)The pooled t-test is extremely nonrobust to violations of the assumption.

Question

Which of the following statements regarding the equal-standard-deviations assumption of the pooled t-test is the most accurate? 
A)The pooled t-test is robust to moderate violations of the assumption provided the sample sizes are large.
B)The pooled t-test is robust to moderate violations of the assumption provided the sample sizes are roughly equal.
C)The pooled t-test is robust to moderate violations of the assumption regardless of the sample sizes.
D)The pooled t-test is extremely nonrobust to violations of the assumption.

Quizplus · Accepted Answer

The pooled t-test assumes that the two populations have equal variances (homogeneity of variances). It is robust to moderate violations of this assumption if the sample sizes of the two groups are roughly equal, because the impact of unequal variances is minimized when the groups are of similar size.

Which of the Following Statements Regarding the Equal-Standard-Deviations Assumption of the Pooled