What is the Wilcoxon Signed Rank Test?
The Wilcoxon signed rank test is a nonparametric hypothesis test that can do the following:
- Evaluate the median difference between two paired samples.
- Compare a 1-sample median to a reference value.
nonparametric
Kruskal Wallis Test Explained
What is the Kruskal Wallis Test?
The Kruskal Wallis test is a nonparametric hypothesis test that compares three or more independent groups. Statisticians also refer to it as one-way ANOVA on ranks. This analysis extends the Mann Whitney U nonparametric test that can compare only two groups. [Read more…] about Kruskal Wallis Test Explained
Mann Whitney U Test Explained
What is the Mann Whitney U Test?
The Mann Whitney U test is a nonparametric hypothesis test that compares two independent groups. Statisticians also refer to it as the Wilcoxon rank sum test. The Kruskal Wallis test extends this analysis so that can compare more than two groups. [Read more…] about Mann Whitney U Test Explained
Nonparametric Tests vs. Parametric Tests
Nonparametric tests don’t require that your data follow the normal distribution. They’re also known as distribution-free tests and can provide benefits in certain situations. Typically, people who perform statistical hypothesis tests are more comfortable with parametric tests than nonparametric tests.
You’ve probably heard it’s best to use nonparametric tests if your data are not normally distributed—or something along these lines. That seems like an easy way to choose, but there’s more to the decision than that. [Read more…] about Nonparametric Tests vs. Parametric Tests