On Sat, 2009-08-29 at 12:56 +0100, Markus Gesmann wrote: > Dear R-help, > > Suppose I have the following data: > > df=data.frame(x=1:10, y=c(1,2,3,4,5,12,14,16,18,20)) > plot(y~x, df, t="b") > > How can I fit a model which estimates the slopes between x = 1-5, 5-6, > and 6-10?
Does the segmented package do what you want? G > > Adding the factor f: > > df$f <- gl(2,5) > > Allows me to fit a linear model with interaction > > lm(y ~ x:f, data=df) > > which gives me the slope of 1 and 2 between 1-5, and 6-10 > respectively, however it can not cope with the change from 5 to 6. > > I would appreciate if someone could point me into the right direction. > > Many thanks > > Markus > > ______________________________________________ > 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. -- %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% Dr. Gavin Simpson [t] +44 (0)20 7679 0522 ECRC, UCL Geography, [f] +44 (0)20 7679 0565 Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/ UK. WC1E 6BT. [w] http://www.freshwaters.org.uk %~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~% ______________________________________________ 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.