I want to run a mediation with a 3-level categorical predictor. Basically, I had participants assigned to 1 of 3 conditions for a vignette study (vignette type: control scenario, high mistreatment scenario, or low mistreatment scenario), I want to see whether vignette type predicts the dependent continuous variable through the continuous mediator.
I am new to R and am not sure how to best go about doing this analysis.
I believe I am supposed to effects code but I am not sure whether this is the proper approach.