My simpleminded understanding of simple regression is that when plotting regression lines for x on y and y on x in the same plot, the lines should cross each other at the respective means. But, given the R function below, abline (lm(y~x)) works fine, but abline (lm(x~y)) does not. Why?
function () { attach (attitude) x <- rating y <- learning detach (attitude) plot (x, y) abline(v=mean(x)) abline(h=mean(y)) abline (lm(y~x)) abline (lm(x~y)) } ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.