[R] GlmmPQL with binomial errors

[Prof Brian Ripley]

glmmPQL is part of MASS, and that is support software for a book.  Do look 
in the book and its references ....

On Sat, 6 Mar 2004, O Tosas Auguet wrote:

> I hope somebody can help me solve some doubts which must be very basic, 
> but I haven't been able to solve by myself.
> 
> The first one, is how to assess for overdispersion in GlmmPQL when fitting 
> binomial or poisson errors. The second one is whether GlmmPQL can compare 
> models with different fixed effects.
> 
> The third doubt, regards the way I should arrange my data in a GlmmPQL with 
> binomial errors. In glm, I am supposed to create cbind vector joining 
> the "number of successes" and the "total-the number of successes". Should I 
> proceed the same way for GlmmPQL of can I use a single column which, intead of 
> containing the numbers, simply contains 0 or 1?. The reason for this question, 
> is that I am trying to fit a variance components analysis with a single random 
> effect and no fixed effects. The only way I know to test for the significance 
> of the single level of random effects is by comparing the model with a glm 
> without fixed effects and do a ChiSquare test. So, should the data of both 
> models be arranged the same way? or is it possible to compare the model with 
> random effects and response "0,1" whith that of a glm without fixed effects 
> where the response is arranged as cbind(successes,total-successes)? My concern 
> of using cbind in GlmmPQL, is that lose replication of the variable of 
> interest, and I have realized that when fitting the random variable as a fixed 
> effect in a simple glm, I end up with 0 residual degrees of freedom.

-- 
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