I am doing a cases study and I need to forecast the sales. I am using multi linear regression and also winter's method and the decomposition approach with Holt's method. I am using these methods as there is a clear upwards trend and seasonality. However when I use excel solver to min MAD i get a gamma =0 (winter's method) and a beta = 1 (for Holt's method). This seems weird to me. The professor told us to not simply use the values that minimize the MAD, but think about what they mean. We have a strong growing market and clear seasonality (and the seasonal pattern will likely stay the same) , what are good values to chose ?
