The<unk>  is a non-parametric alternative to the paired Student's t-test for the case of two related samples or repeated measurements on a single sample. The test is named for Frank<unk>  (1892–1965) who, in a single paper, proposed both it and the<unk> -sum test for two independent samples<unk> , 1945).
Like the t-test, the<unk>  test involves comparisons of differences between measurements, so it requires that the data are measured at an interval level of measurement.  However it does not require assumptions about the form of the distribution of the measurements.  It should therefore be used whenever the distributional assumptions that underlie the t-test cannot be satisfied.
Wilcoxon signed-rank test
Kendall tau rank correlation coefficient
Chi-square test
Analysis of variance
Shapiro-Wilk test
Analysis of covariance
Analysis of rhythmic variance
Likelihood-ratio test