Nonparametric tests, often known as distribution-free tests, are statistical tests that make no assumptions about the data's distribution. Nonparametric tests are based on ordinal variables or the rank of values in the data.
Use it WHEN
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The median represents the center of data distribution
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The Sample size is large or small
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The data is not normally distributed
Data that is assumed to not have a normal distribution can be analyzed using the following statistical analyses:

Each parametric test has its equivalent non-parametric test that is given in the below image