If a violation of the homogeneity of variance assumption occurs, it is always necessary to abandon use of the t test for an independent groups design.

Question

Quizplus · Accepted Answer

If the violation of homogeneity of variance is mild to moderate and the sample sizes between groups are equal or nearly equal, the t test can still be used. If the violation is severe or the sample sizes are unequal, other statistical tests such as Welch's t-test or the Mann-Whitney U test may be more appropriate.

If a Violation of the Homogeneity of Variance Assumption Occurs