On Fri, 2 May 2003, Peter B. Mandeville wrote:
>
> Based on the stepAIC help, I have assumed that it only was for lm, aov, and
> glm models.
Even though the help does not mention those classes, and the book actually
uses stepAIC for coxph?
> I gather from the following correspondence that it also works
> with lme models.
>
> Thomas Lumley 07:40 a.m. 28/04/03 -0700 4 Re: [R] stepAIC/lme problem
> (1.7.0 only)
> Prof Brian Ripley 04:19 p.m. 28/04/03 +0100 6 Re: [R] stepAIC/lme problem
> (1.7.0 only)
> Prof Brian Ripley 06:09 p.m. 29/04/03 +0100 6 Re: [R] stepAIC/lme problem
> (1.7.0 only)
>
> I am using windowsXP and have experimented with the data set HR from the
> SASmixed library without success with rw1.6.2.
>
> I would greatly appreciate the correct syntax for version rw1.6.2.
It's as described on the help page, and in Robert Cuffe's example (to
which those were replies).
data(HR)
fm1HR <- lme(HR ~ Time * Drug + baseHR, data = HR,
random = ~ Time | Patient, method = "ML")
stepAIC(fm1HR)
works. What could be simpler? (And you can't use method="REML"
as this
is step*AIC*.)
[And that works in 1.7.0 if you update VR.]
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595