Relationships · Interactive concept

Comparing Groups with Ranks

What changes when we replace observed values with their ranks?

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Why compare ranks?

A few extreme values can strongly affect a mean. The Wilcoxon rank-sum test—also called the Mann–Whitney test—asks whether observations from two independent groups tend to occupy different positions in their pooled ordering.

Data structure: one quantitative or ordinal outcome, two independent groups, and independent observations within and across groups.

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