R^2 for a model is usually defined as 1-RSS/TSS where TSS is the SS about the mean and RSS is the residual SS from the model.
Consider the model in R z <- runif(20) y <- z+rnorm(20) my.model <- lm(y~offset(z)) summary(my.model)$r.squared Here the RSS is equivalent to the TSS and gives 0 when it should (IMHO and a few others perhaps) be 1 - RSS/TSS(corrected for the mean only) RSS = sum(resid(my.model)^2) TSS = sum((y-mean(y))^2) Have I missed this somewhere in the FAQ's or elsewhere? Regards Ross Darnell ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
