> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of David Epstein > Sent: Wednesday, September 10, 2008 1:06 PM > To: r-help@r-project.org > Subject: [R] re flecting a line > > > Suppose x and y are numeric vectors of the same length. > > plot(x,y) #scatterplot > lmObj1 <- lm(y~x) # best fit line > abline(lmObj1) # good > lmObj2 <- lm(x~y) #get best fit but with axes interchanged > abline(lmObj2) # not what I want. I want the correct line, > drawn on the same > graph, but with > # response and predictor variables interchanged > > One way to proceed would be to extract the intercept and > slope from lmObj2 > and then do the arithmetic to draw the correct line. I'm > hoping for a more > streamlined method. Is there one? > > Thanks > David
Is something like this what you are looking for? x <- 1:100 y <- 10 + x + 10*rnorm(100) plot(y~x) fit1.lm <- lm(y~x) abline(fit1.lm, col='blue') fit2.lm <- lm(x~y) abline(-coef(fit2.lm)[1]/coef(fit2.lm)[2], 1/coef(fit2.lm)[2], col='red') Hope this is helpful, Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 ______________________________________________ R-help@r-project.org 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.
