Inspiring Insights from Data Analysis

What type of data is suitable for the Kruskal-Wallis H test?

Do you know what scale the dependent variable should be on for the Kruskal-Wallis H test to be applicable?

Answer:

The Kruskal-Wallis H test requires the dependent variable to be on an ordinal scale, or a continuous scale that has been converted to ranks. It compares the medians of groups, which distinguishes it from tests like the Aspin-Welch t-test that compare means.

The Kruskal-Wallis H test is a powerful nonparametric test that is used to compare two or more independent samples. In order for the test to provide reliable results, the dependent variable (dv) needs to be measured on an ordinal scale or a continuous scale that has been converted to ranks.

Unlike parametric tests that rely on assumptions about the underlying distribution of the data, the Kruskal-Wallis H test focuses on comparing medians rather than means. This makes it suitable for data that may not meet the normality assumption required by parametric tests.

Examples of data that are suitable for the Kruskal-Wallis H test include satisfaction survey scores (e.g., rating from 1 to 5) and rankings of athletic performance (e.g., first place, second place, etc.). These types of data are naturally ordinal or can be converted into ranks, making them ideal for comparison using this nonparametric test.