Introduction to Analysis of Covariance: One- Factor Fixed-Effects Model With Single Covariate

We have now considered several different analysis of variance (ANOVA) models. As we moved through Chapter 3, we saw that the inclusion of additional factors helped to reduce the residual or uncontrolled variation. These additional factors served as “experimental design controls” in that their inclusion in the design helped to reduce the uncontrolled variation. In fact, this could be the reason an additional factor is included in a factorial design.