Using SAS for Multicollinearity:

Data File: mantel

Using these 'data' with a response Y and three regressors X1, X2, and X3 from Mantel (1970), complete the follow:

Apply the forward selection. What is the starting value of R-squared to two decimal places? What is the first regressor added to the model? Apply the backward selection. True or False, this produces the same model as was produced with forward selection. Apply forward and backward selection using r-squared. Which model is preferred (Y~X3 or Y~X1+X2+X3)?

If you could post the code and screenshots of results, I would really appreciate it. I'm struggling with how to write steps of the code and understanding exactly what I'm looking at in the results. Thanks!

This is the data for mantel:

VAR1	Y	X1	X2	X3
1	5	1	1004	6
2	6	200	806	7.3
3	8	-50	1058	11
4	9	909	100	13
5	11	506	505	13.1