[R] lme correlation structures

From: Gareth Hughes <ghughes.email_at_gmail.com>
Date: Wed, 27 Jun 2007 15:50:24 +0100


Hi all,

I've been using SAS proc mixed to fit linear mixed models and would like to be able to fit the same models in R. Two things in particular:

  1. I have longitudinal data and wish to allow for different repeated measures covariance parameter estimates for different groups (men and women), each covariance matrix having the same structure. In proc mixed this would be done by specifying group= in the REPEATED statement. Is this simple to do in R? (I've tried form=~time|indv/sex for example but this doesn't seem to do the job).
  2. I've read that other correlation structures can be specified. Does anyone have any examples of how toeplitz or (first-order) ante-dependence structures can be specified?

Many thanks,

Gareth



R-help_at_stat.math.ethz.ch 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. Received on Wed 27 Jun 2007 - 15:27:56 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Wed 27 Jun 2007 - 16:32:17 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.