order statistics

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order statistics A branch of statistics that uses not the numerical value of an observation but its ranking relative to other observations. The rth order statistic of a sample of n observations is simply the rth smallest variate value in the sample. Examples of statistical tests for ordering include: the median test, the sign test, Cochran's test, the Wald-Wolfowitz “runs test”, the Mann-Whitney test, the Wilcoxen test, the Kruskal-Wallis test, and the Friedman test.