Message-ID: <20111108155357.56CB.F023FAF3@mpi-bpc.mpg.de>
Date: 2011-11-08T14:53:57Z
From: Holger Taschenberger
Subject: compare linear regressions
In-Reply-To: <CADtGJG1KhEacekGhNW0HccYwKnz8c6LUhRzdta8n9KWboUyy0g@mail.gmail.com>
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.