Why do we use nonparametric tests?© BrainMass Inc. brainmass.com March 21, 2019, 6:00 pm ad1c9bdddf
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If a statistical variable understudy can be represented on a ratio or at least an interval scale of measurement, then it is said to have proper units. With some assumption made about the distribution of the variable (say normality, for example), the variable is fit to be tested parametrically. The t-test, the z-test etc are a few well-known parametric testing methods. But these tests lay different restrictions on the data.
If a statistical variable is of the ...
This solution contains a comprehensive answer to why non-parametric tests are used.