Is it true that parametric tests are generally more powerful

Is it true that parametric tests are generally more powerful than nonparametric tests? If so, give two reasons why you might choose to use a nonparametric test instead of a parametric test

Solution

Nonparametric tests are also called distribution-free tests because they don’t assume that your data follow a specific distribution. For a parametric test the distribution is assumed to be Normal and the varaince is homogenous. The samples drawn are independent in case of parametric distribution while in non parametric distribution the condition of independacy is not required.

In general we can say that the Nonparametric tests are general and can be used for any distribution