This article discusses the basic characteristics of nonparametric statistical tests, contrasting them with the characteristics of parametric statistical tests. Examples for performing nonparametric statistical tests on practitioners' own data also are included.
Nonparametric tests can be used with data that are of the nominative (e.g., characteristics such as right and left, male and female) and ordinal (e.g., mild, moderate and severe) levels of measurement, which may not follow the normal distribution curve or comply with other assumptions required of data analyzed by parametric statistical methods. However, the results of analyzing data with these nonparametric statistical methods can yield important information about the degree to which qualities of one group of data differ from those of another group.
© 1996 American Academy of Orthotists & Prosthetists