Thank you. I was confused because the output of the line "summary(lm(formula =..." reads: "Coefficients: (1 not defined because of singularities)", which did not look like a normal message (which can safely be ignored) to me. --Holger On Tue, 8 Nov 2011 15:06:28 +0100
Peter Konings <peter.l.e.konings at gmail.com> wrote:
On Tue, Nov 8, 2011 at 2:52 PM, Holger Taschenberger < Holger.Taschenberger at mpi-bpc.mpg.de> wrote: <snip>
summary(lm(formula = y ~ x - 1 + x:g, dta)) ################## I assume that the last line is the correct way to specify a linear model without intercept. But I'm not certain about that. Can someone please confirm?
Yes, that's true. See chapter 11 of the "Introduction To R" manual that was installed with R for an overview of model specification in R. HTH Peter.