A non-parametric method to compare two populations, when the samples are independent but the assumptions behind the independent samples t-test are violated, is the:
A) Wilcoxon rank sum test.
B) sign test.
C) matched pairs t-test.
D) Wilcoxon signed rank sum test.

Question

Quizplus · Accepted Answer

The Wilcoxon rank sum test is a non-parametric method that can be used when the assumptions behind the independent samples t-test are violated. This test does not require the assumption of normality or equality of variances, and instead ranks the observations in both samples and compares the medians. Therefore, it is a suitable choice for comparing two populations when the assumptions of the independent samples t-test are violated.

A Non-Parametric Method to Compare Two Populations, When the Samples