I'm a little stuck on my data analyses for my thesis. My experiment is about EMDR and has two conditions (Recall+eye movements and recall only). Goal of the experiment is to see if the recalled image during the session is less vivid, emotional and distressing after the intervention ((Recall+eye movements or recall only). So the outcome measures are VIV, EMO and SUD (distress). These are measured on VAS scales from 0 to 100. The intervention starts with a pretest (measured 3 times), then the intervention (recalling the memory 8 times with of without EM), a posttest (3x) and a 24h follow up (also measured 3 times). So I have a lot of data. I also look at the primary emotional reaction to the memory. Participants fill in 7 VAS scales of emotions (for example sadness, fear and anger) before the recall session begins. I want to know if the primary emotion influences the effect of EMDR. My mentor said that I would have to do a stepwise regression. I would first have to include the main effect of time, then the main effect of the emotions and lastely the interaction effect of time x memory. I have no idea how to include the main effect of time. I know time is pretest, posttest, follow up, but the results of these are already the dependent variables. so what is the independent variable if I want to know the main effect of time???