What is non parametric test?

A non-parametric test is a type of statistical test that does not assume a specific distribution for the data, making it suitable for analyzing data that may not meet the assumptions of parametric tests. These tests are often used for ordinal data or when sample sizes are small. Common examples include the Mann-Whitney U test and the Kruskal-Wallis test. Non-parametric tests are typically more robust to outliers and can be applied to a wider range of data types.