rank sum test

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rank sum test

a nonparametric statistical test for ordinal data, testing the null hypothesis that two samples are drawn from the same population against the alternative hypothesis that the two samples are drawn from two populations having probability distributions of the same shape but different locations. It is based on the value of the rank sum statistic, which is calculated as the sum of the ranks of each sample after the observations in both samples are jointly ranked in ascending order; if and only if the null hypothesis is true, the average ranks of the two samples will be similar. Also called Mann-Whitney test, Mann-Whitney U test.

Mann-Whitney test

A statistical test of the probability that two independent sets of observations come from the same population. The Mann-Whitney test is independent of distribution and can be used when the t test is inappropriate.


the place in a series occupied by a value when the series has been set in order according to a particular trait, usually size. Called also order statistic.

rank sum test
nonparametrical statistical test used to compare two methods by seeing if one method contributes more to the higher ranked values.
References in periodicals archive ?
the Friedman rank sum test, was run; this additional analysis gave results coherent with those of ANOVA at the classical significance level of [alpha] = 0.
4 m2/ha xerophytic oaks, n = 254; Wilcoxon rank sum test, P = 0.
CW was significantly different between species (Wilcoxon's rank sum test, P < 0.
All rank sum tests except those for the first period are performed with groups as independent observations to take the dependency of decisions within a group into account.
54 [micro]g/l) and no significance was found on Wilcoxon rank sum test (P=0.
The Wilcoxon rank sum test was used to determine the probability of the blood sample communities and the NHANES data subjects being drawn from congruent populations with the same true mean and distribution.
Therefore, we conducted a separate signed rank sum test and correlation analysis to estimate the association between AD and CE, as well as correlation analyses to estimate associations between AD-CE and the aforementioned four combinations.
Based on the Wilcoxon Rank Sum test, there was no significant difference at the 0.
For every incipit, we used the Wilcoxon rank sum test to compare the list of ranks assigned to it with the lists of ranks assigned to its predecessors.
A Mann-Whitney Rank Sum test was performed to determine statistical significance.