# Wilcoxon test (paired samples)

Command: | Statistics Rank sum tests Wilcoxon test (paired samples) |

## Description

The Wilcoxon test for paired samples is the non-parametric equivalent of the paired samples t-test. It should be used when the sample data are not Normally distributed, and they cannot be transformed to a Normal distribution by means of a logarithmic transformation.

## Required input

Select the variables for sample 1 and sample 2, and a possible filter for the data pairs. You can use the button to select variables and filters in the variables list.

## Results

The Wilcoxon test for paired data ranks the absolute values of the differences between the paired data in sample 1 and sample 2 and calculates a statistic on the number of negative and positive differences (differences are calculated as sample 2 - sample 1).

## Literature

- Altman DG (1991) Practical statistics for medical research. London: Chapman and Hall.

## See also

- To perform different tests in one single procedure, see Comparison of paired samples
- Signed rank sum test (one sample)
- Mann-Whitney test (independent samples)

## External links

- Wilcoxon signed-rank test on Wikipedia.