Answer to Question 1
The Wilcoxon rank sum test compares two independent samples, while the Wilcoxon signed rank test can be used to compare two dependent samples. The Wilcoxon rank sum test should be used with independent samples, and the signed rank test should be used when dealing with pairs.
Answer to Question 2
The parametric counterpart to the Wilcoxon signed rank test for paired samples is the paired samples t-test. Both tests assume continuous data on the interval or ratio scale, and the data come in pairs. The t-test assumes that both underlying populations are normally distributed, whereas the Wilcoxon test assumes only that both distributions are fairly symmetric in shape.
The upper panel shows that scores of four diverse samples of boys on a moral reasoning test show a ...
Photo of a sign taken at an emissions test facility.
A vehicle being tested during an enhanced emissions test.
A Mono-Diff test in which the presumptive well contains the patient's serum mixed with ...
The Ames test, which screens compounds for potential mutagenicity
Emerson’s Three-Point Test-Cross Analysis