
102 Nonparametric Statistics for Social and Behavioral Sciences
the combined groups. One group will have observations at or below the
median and the second group will have observations above the median.
The Wilcoxon-Mann-Whitney U test is considered more powerful than
the median test because the rank of each observation is considered instead
of only the relation of a score to the median value in the distribution. The
Wilcoxon-Mann-Whitney U test is discussed in Section 4.3.
4.3 Wilcoxon-Mann-Whitney U Test
The Wilcoxon-Mann-Whitney U test is a counterpart to the parametric inde-
pendent samples t-test for evaluating whether two samples were dra ...