n regression, we are often interested in an interaction, which is the modification or moderation of the effect of an independent variable by another. Understanding interactions involves interpreting the regression coefficients, estimating and testing simple effects and their differences, and visualizing the interaction. This workshop will teach you how to do all of these thing in R using base R, as well as the emmeans and ggplot2 packages. Some prior knowledge of linear regression and experience with R is recommended but not necessary.