by **StlSluggers** » Fri Jul 08, 2005 12:25 pm

Mr. Pimp (or anyone else),

Maybe you can help me with some logic on this. run this regression analysis twice. The first time I ran it with two variables, but I realized that the first variable was actually the product of two other variables, so I separated it out into it's respective pieces and re-ran the numbers, which are what I posted in the first post.

Here are the R-squared measurements of some variables from each formula:

X1: 0.49799

Y: 0.31052

X1&Y: 0.90940

X2: 0.61531

Y: 0.31052

Z: 0.00363

X2&Y: 0.81803

X2 became more descriptive than X1, which makes sense because I pulled out the irrelevant part by segregating variable Z. However, the original combination of X1 and Y was actually more descriptive than X2 and Y in the new equation, and that makes absolutely no sense to me.

Can anyone explain how making one variable more descriptive actually made the combination of that variable and a constant less descriptive in the new formula?