[R] Regression lines

From: Tom Backer Johnsen <backer_at_psych.uib.no>
Date: Fri 12 Jan 2007 - 09:39:23 GMT


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))

}

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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. Received on Fri Jan 12 20:47:18 2007

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