if I have the two following matrices, abline(0,1) doesn't go through. QQplot is attached.
[,1] [,2] [,3] [,4] [,5] 2.149644 1.992864 3.346375 2.793511 3.428230 1.100762 2.152981 2.735401 2.175185 3.323058 1.212406 2.131813 2.672598 2.389996 3.242490 1.183770 1.908633 2.661237 2.590545 2.906059 1.665190 1.778923 2.636062 2.475619 4.013407 0.601 0.083 0.520 0.920 -0.007 -0.778 0.427 -0.605 -0.066 -0.283 -0.599 0.348 -0.693 0.284 -0.436 -0.519 0.081 -0.590 0.678 -1.095 0.009 -0.253 -0.940 0.526 1.623 --- On Mon, 11/2/09, David Winsemius <dwinsem...@comcast.net> wrote: > From: David Winsemius <dwinsem...@comcast.net> > Subject: Re: [R] qqplot > To: "carol white" <wht_...@yahoo.com> > Cc: r-h...@stat.math.ethz.ch > Date: Monday, November 2, 2009, 8:17 AM > > On Nov 2, 2009, at 10:40 AM, carol white wrote: > > > 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? > > I always assumed that the intercept was zero and the slope > = unity. > > y <- rt(200, df = 5) > qqnorm(y); qqline(y, col = 2) > qqplot(y, rt(300, df = 5)) > abline(0, 1, col="red") > > I am open to education if that assumption is too > simplistic, but you have not offered anything in the way of > a counter-example. > > > > == > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > >
<<attachment: qqplot.png>>
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