Inference for causal effects is a critical activity in many branches of science and public policy. The field of statistics is the one field most suited to address such problems, whether from designed experiments or observational studies. Consequently, it is arguably essential that departments of statistics teach courses in causal inference to both…

This article presents a technique that will help teachers, researchers, and other people who use the linear regression models, especially those in education and social sciences, to understand and interpret the residuals graphics better.