This version of PhStat has this feature, the previous one did not. Before Excel, I used SPSS as statistics software and it used stepwise regression. All that it is is a technique for deciding which independent variables should be in a regression model. Obviously, it is needed only when there are several possibilities and we may not want to just blindly put all into the model. In many real life examples, there may be 20 to 50 possible independent variables and we go on a search mission to find which are good predictors of the dependent variable. Stepwise regression is a decision model that only enters variables when it makes sense, statistically, to enter the variable. You specify the criteria for entering. There are variations for stepwise regression -- forward and backward which are just various ways to enter the variables. The text explains this. There are large data sets in the text that you want to try using stepwise regression.