Carol, You could run a line through the pairs of first and third quartiles of the two distributions, i.e., c(quantile(x, .25), quantile(y, .25)) and c(quantile(x, .75), quantile(y, .75)). (Of course, you'd want the line to extend across the whole graph.)
I hope this helps, John > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of carol white > Sent: November-02-09 10:40 AM > To: r-h...@stat.math.ethz.ch > Subject: [R] qqplot > > Hi, > We could use qqplot to see how two distributions are different from each > other. To show better how they are different (departs from the straight > line), how is it possible to plot the straight line that goes through them? I > am looking for some thing like qqline for qqnorm. I thought of abline but how > to determine the slope and intercept? > > Best wishes, > > Carol > > ______________________________________________ > 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. ______________________________________________ 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.
