I want to perform a Multiple regression analysis on my dataset. My data set has approximately 10 Independent variables which I want to use to predict the variation in my dependent variable. In the Multiple regression analysis i want to perform the backward selection.
My question/problem is as follows:
Is it possible to group a couple of the independent variables as one? so that in backward selections SPSS see is as one variable?
here an example...
a couple of Independent variables are: weight, age, sex, length. Is it possible to group these IV to one? say a group variable name with: "clinical facotrs" so that SPSS takes these four 'of the model' at once during backward selection? (excuse me for my bad english
Thanks in advance,