10-14-2013 12:11 AM
I'm new to SAS and studying a forecasting problem for the sales of a kind of soft drink. I have about 20 variables(including week, price, competitors price/volume, promotion dummy, holiday/season dummy) and 100 weeks data.
I used stepwise/forward/backward to select some variables first. It turns out the best model is forward and I got about 10 variables from it. Then I tried to do the pooled regression using proc mixed but I don't know what to put in random statement what to put in sub= etc. I searched a lot and most examples only have two or three variables. I got so confused, anyone can help me?