A biological perspective on interpreting interaction effect

Abstract

Factorial experiments are commonly employed in agricultural research as in other branches of applied sciences. In these experiments, inferences related to the interaction are essential. However, many researchers are still unable to analyze this type of experiment and interpret the results in the correct way. This is because researchers focus on interpreting the main effects although there is a significant interaction effect. Of course, meaningful main effects can exist even in the presence of an interaction, especially if interactions do not affect the main effects. Therefore, it is extremely important to understand thoroughly in which situations only the interaction effect(s), in which cases only the main effect(s), and in which cases the interpretation of the main effects will be meaningful although the interaction effect is significant. In this study, evaluating factorial experiments has been discussed in detail, especially in studies related to animal science. It has also been focused on the importance of considering both statistical and practical significance while interpreting the statistical analysis results.