The Wilcoxon rank- sum test requires the data be at least at the ordinal level of measurement and that the shapes of the distributions for the two populations are similar.

Question

Quizplus · Accepted Answer

The Wilcoxon rank-sum test, also known as the Mann-Whitney U test, requires that the data be at least ordinal because it ranks the observations. Additionally, for the test to be most effective, it assumes that the distributions of the two populations are similar in shape, though it does not require them to follow a normal distribution.

The Wilcoxon Rank- Sum Test Requires the Data Be at Least