A Primer on the Johnson-Neyman Technique: An Alternative Procedure to ANCOVA

Abstract

The homogeneity of regression coefficients is one of the most important assumptions for appropriate of ANCOVA (Huitema, 1980). However, this assumption is not always met, but usual to reveal the heterogeneity of slopes, and thus leading to biased statistical testing results. Hence, an alternative approach to ANCOVA is required. In the present paper, Johnson- Neyman technique is briefly introduced including a sequence of statistical tests and Statistical Package Syntax.