I've made some normal plots of my data using qqplot, and now I would like to fit a line to the points on the plot and check the correlation coefficient to have a more objective measure of how straight the line is. Is there a simple way of doing that? (I'm still pretty new to R.) Thanks, --Paul -- Paul Lynch Aquilent, Inc. National Library of Medicine (Contractor)
Paul Lynch wrote:> I've made some normal plots of my data using qqplot, and now > I would like to fit a line to the points on the plot and > check the correlation coefficient to have a more objective measure > of how straight the line is. Is there a simple way of doing that? > (I'm still pretty new to R.)See ?qqplot and what its value is: x <- rnorm(10) y <- rnorm(10) qq <- qqplot(x, y) cor(qq$x, qq$y) Uwe Ligges> Thanks, > --Paul >
See also ?shapiro.test which is effectively based on this correlation coefficient. On Fri, 2007-03-23 at 00:13 -0400, Paul Lynch wrote:> I've made some normal plots of my data using qqplot, and now > I would like to fit a line to the points on the plot and > check the correlation coefficient to have a more objective measure > of how straight the line is. Is there a simple way of doing that? > (I'm still pretty new to R.) > > Thanks, > --Paul >School of Biological Sciences, University of Edinburgh