In the application of statistical treatments, two types of data are recognized:

1. Parametric Data - data which is measured and which is assumed to be normally or near normally distributed. Examples include most standardized tests such as I.Q. tests, S.A.T., G.R.E., etc.


2. Non-Parametric Data - data which is distribution-free, and which is generally counted or ranked. Examples include demographic data such as sex or ethnicity; and categorized data such as pass/fail, responses such as yes/no.