Which Wilcoxon test to use?
Wilcoxon rank sum? Wilcoxon signed rank? Wilcoxon one-sample? Two sample? Mann-Whitney U? If you are confused, read on.
All of these are basically non-parametric versions of the t-test.
That is, you want to check if two groups of numbers have a similar distribution/center (without the normal distribution assumption in a t-test).
Here is a quick guide that I made for myself (and you!):
Wilcoxon rank sum (same as “Mann–Whitney U test”)
Basically, like your standard t-test to compare two samples from two different populations.
wilcox.test(df$X, df$Y) # both numeric wilcox.test(y ~ A) # A is a group/factor
Use when comparing two related samples, matched samples, or repeated measurements on a single sample.
wilcox.test(df$Y1, df$Y2, paired=TRUE)
A handy R reference for this: