[R-sig-ME] Running repeated measures in lme4

[Emma Stone]

Hi Ben,

Thanks for your reply, however I have re ran this and I still get zero 
group variance. Also, forgive my ignorance but doesn't this code remove the 
repeated measures element of the design? Also for note, I ran my code with 
a poisson distribution and I did get variance outputs for the Random Group 
level.

Emma

--On 03 March 2010 07:28 -0500 Ben Bolker <bolker at ufl.edu> wrote:

> Emma Stone wrote:
>> Dear all,
>>
>> I wander if you can help.
>>
>> I am running a repeated measures model with lmer.I have 8 sites, at each
>> I  conducted an experiment with treatments which have 4 levels. Each
>> treatment  was conducted only once per site, but each site has one of
>> each of the  treatment levels so it is balanced. Obviously the
>> treatments within sites  are the repeated measures component, and I want
>> to look at differences  between treatments within sites, I am not really
>> interested in the site  group effect but need to incorporate it. So I
>> have set up my model as  follows:
>>
>> model1<-lmer~(minutes~treatment+(treatment|site), data = data)
>
>   This model fits a site by treatment interaction, which you don't
> have enough information for since you don't have replication.  I believe
> you want
>
> model1<-lmer~(minutes~treatment+(1|site), data = data)
>
>
> --
> Ben Bolker
> Associate professor, Biology Dep't, Univ. of Florida
> bolker at ufl.edu / people.biology.ufl.edu/bolker
> GPG key: people.biology.ufl.edu/bolker/benbolker-publickey.asc



----------------------
Emma Stone
Postgraduate Researcher
Bat Ecology and Bioacoustics Lab
& Mammal Research Unit
School of Biological Sciences,
University of Bristol, Woodland Road,
Bristol, BS8 1UG
Email: emma.stone at bristol.ac.uk