A nonparametric method to compare two or more populations, when the samples are matched pairs and the data are either ordinal or interval but not normal, is:
A) the Wilcoxon signed rank sum test
B) the sign test
C) the Friedman test
D) the Kruskal-Wallis test
E) none of these

Question

Quizplus · Accepted Answer

The Friedman test is a nonparametric method used to compare two or more populations when samples are matched pairs and the data are either ordinal or interval but not normal. This test is appropriate when the same participants are studied under different treatments or conditions, and the data are dependent. The Wilcoxon signed rank sum test and the sign test are appropriate when there are only two populations being compared, but the Friedman test can handle more than two populations. The Kruskal-Wallis test is used when the data are independent and ordinal or interval, but not normal, and there are more than two populations being compared.

A Nonparametric Method to Compare Two or More Populations, When