RT Book, Section A1 Portney, Leslie G. SR Print(0) ID 1186214483 T1 Nonparametric Tests for Group Comparisons T2 Foundations of Clinical Research: Applications to Evidence-Based Practice, 4e YR 2020 FD 2020 PB F. A. Davis Company PP New York, NY SN 9780803661134 LK fadavispt.mhmedical.com/content.aspx?aid=1186214483 RD 2024/03/28 AB In previous chapters several statistical tests have been presented that are based on certain assumptions about the parameters of the population from which the samples were drawn. These parametric tests are appropriate for use with ratio/interval data. In this chapter, we present a set of statistical procedures classified as nonparametric, which test hypotheses for group comparisons without normality or variance assumptions and are appropriate for analysis of nominal or ordinal data. For this reason, these methods are sometimes referred to as distribution-free tests. The data for these tests are reduced to ranks, and comparisons are based on distributions, not means.