I am doing a stability study, for which I have several lots on different storage temperatures. In order to asses the stability I want to do a pooled regression analysis, but first I have to check in my GLM, whether there are differences in the intercepts and the slopes, otherwise I am not allowed to pool them.
So far so good, but here is the tricky part: I also want to see if there are differences between the storage temperatures. For this, I do no longer use individual lots, but the data for all lots combined. There is no concern doing this, if the slopes and intercepts are not significantly different for each temperature, but is it also valid to do this, if there actually is a significant different?
I`m having a similar problem, just many steps behind. I`ve always been terrible with stats and now it seems I can`t get what goes into which column . Problem, pretty much the same: want to check if I can combine the lots from the same temperature, using the same criteria: are there significant differences in their slopes and intercepts. It seems you are way passed this part. Can you, please, help me do it? I have 3 lots, 36 months data for all of them. The file is attached. Thank you!