Nonparametric Statistical Methods Using R

Chapter 5

ANOVA and ANCOVA

5.1 Introduction

In this chapter, the R functions in the packages Rfit and npsm for the computation of fits and inference for standard rank-based analyses of variance (ANOVA)1 and analysis of covariance (ANCOVA) type designs are discussed. These include one-way, two-way, and k-way crossed designs that are covered in Sections 5.2, 5.3 and 5.4. Both tests of general linear hypotheses and estimation of effects with standard errors and confidence intervals are emphasized. We also briefly present multiple comparison procedures (MCP), in particular a robust Tukey–Kramer procedure, illustrating their computation via the package Rfit. We also consider the R computation of several traditional nonparametric methods for these ...