What is the difference between main effects and interaction effects?

What is the difference between main effects and interaction effects?

Main effects refer to the individual impact of each independent variable on the dependent variable, while interaction effects occur when the effect of one independent variable on the dependent variable changes depending on the level of another independent variable.

Can you give me an example of each?

Sure! For main effects, if you're studying the impact of study time and sleep on test scores, the main effect of study time is how much studying alone affects scores. An interaction effect would be if the impact of study time on scores changes based on how much sleep a student gets.

How do I test for interaction effects in my analysis?

You can test for interaction effects by including an interaction term in your regression model, which is the product of the two independent variables. This allows you to see if the relationship between one variable and the outcome changes at different levels of the other variable.

What statistical software can I use to analyze these effects?

You can use software like R, Python (with libraries like statsmodels), SPSS, or SAS to analyze main and interaction effects in your data.