On Tuesday, August 19, 2003, at 09:20 PM, Simon Blomberg wrote:
You need to look at Analysis of Covariance in any basic stats book.
Basically, if you have y versus x for 2 groups ("group" is a factor),
use lm to fit the model:
fit <- lm(y ~ group + x + x:group, data=your.dat)
but, my situation is two separate regressions with different collected Y's and a predicted X.