Wilcoxon Signed-Rank Test in R

This test can be divided into two parts: 

• One-Sample Wilcoxon Signed Rank Test
• Paired Samples Wilcoxon Test

The Wilcoxon signed-rank test is a non-parametric statistical hypothesis test used to compare two related samples, matched samples, or repeated measurements on a single sample to estimate whether their population means ranks differ e.g. it is a paired difference test. It can be applied as an alternative to the paired Student’s t-test also known as “t-test for matched pairs” or “t-test for dependent samples” when the distribution of the difference between the two samples’ means cannot be assumed to be normally distributed. A Wilcoxon signed-rank test is a nonparametric test that can be used to determine whether two dependent samples were selected from populations having the same distribution.