The Spearman rank-correlation test is a nonparametric test that uses the directions of differences observed in a matched-pairs sample to determine whether the relative frequency distributions of two statistical populations are identical to or different from one another.

Spearman Rank-Correlation

A nonparametric measure of rank correlation, assessing how well the relationship between two variables can be described using a monotonic function.

Nonparametric Test

A type of statistical test that does not rely on data belonging to any particular distribution.

Matched-Pairs Sample

A sampling technique in which pairs of subjects are matched on key characteristics, and differences within pairs are analyzed.