Comparing Two Non-Parallel Regression Lines with the Parametric Alternative to Analysis of Covariance Using SPSS-X or SAS—The Johnson-Neyman Technique

Abstract

The Johnson-Neyman (J-N; 1936) technique is a parametric alternative to analysis of covariance that permits non-parallel regression lines. This article presents computer programs for J-N using the transformational languages of SPSS-X and SAS. The programs are designed for two groups and one covariate.