The Interpretation of Regression Analysis and the Covariance Adjustment, with Particular Reference to Agricultural Research

Abstract

SUMMARYThe aim of this paper is to help biologists gain a clearer understanding of what is involved in covariance analysis. It is an exposition on the derivation of the regression coefficient in the analysis of covariance, and hence on the interpretation of the covariance adjustment. The covariance adjustment is shown to be equivalent to regressing the residuals from an analysis of variance of the original variate on the residuals from an analysis of variance of the covariate.