what is the nonparametric method 
the nonparametric method refers to a type of statistic that does not make any assumptions about the characteristics of the sample its parameters or whether the observed data is quantitative or qualitative nonparametric statistics can include certain descriptive statistics statistical models inference and statistical tests the model structure of nonparametric methods is not specified a priori but is instead determined from data the term nonparametric is not meant to imply that such models completely lack parameters but rather that the number and nature of the parameters are flexible and not fixed in advance a histogram is an example of a nonparametric estimate of a probability distribution in contrast well known statistical methods such as anova pearson s correlation t test and others do make assumptions about the data being analyzed one of the most common parametric assumptions is that population data have a normal distribution 