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 selection criterion for the data pairs. You can use the button to select variables and selection criteria 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

• Signed rank sum test (one sample)
• Mann-Whitney test (independent samples)

External links

• Wilcoxon signed-rank test on Wikipedia.