Wilcoxon rank-sum test

a statistical test of centrality for ranked data that compares the median values of two independent samples to determine whether they have been drawn from the same population. In this nonparametric equivalent of the t test, one combines the data points from the different groups into a single pool and ranks their values in ascending order. The ranks that have been assigned are, in turn, used to determine the test statistic, W, which is evaluated for statistical significance. The calculations involved in the Wilcoxon rank-sum test are nearly identical to those for the Mann–Whitney U test. [Frank Wilcoxon]

Browse dictionary by letter

a b c d e f g h i j k l m n o p q r s t u v w x y z

Psychology term of the day

March 17th 2025

family study

research conducted among siblings, parents, or children to assess evidence for genetic links for characteristics or outcomes, often related to health or disease. For example, a family study might be conducted to assess whether individuals from the same family who share a similar genetic structure also have similar responses to a health-promotion intervention such as diet, exercise, or medication. The extent to which performance on a given measure varies as a function of genetic similarity is used as an indication of the heritability of that measure.