[R] interpretation output glmmPQL

[Lorenz.Gygax@fat.admin.ch]

> We study the effect of several variables on fruit set for 44 
> individuals (plants). For each individual, we have the number
> of fruits, the number of flowers and a value for each variable.
> ...
> - Glm does not take account of the correlation between the
> flowers of a unique individual. So we would like to add a 
> random effect 'individual' but the model2 (here after) gives an
> output similar to the one of model1 for estimated coefficients
> and p-values. 
> ...
> Does it mean that there is no individual effect or is my model
> not good (number of groups (individuals)=number of observations,
> is it possible?).

If you have only one observation per indiviudal plant, how could there be
dependence within the plant? This would only make sense if your observations
were the individual flowers. Data on those could be correlated within plant
and then a random term for the plant is meaningful.

Cheers, Lorenz
- 
Lorenz Gygax
Centre for proper housing of ruminants and pigs
Swiss Federal Veterinary Office
agroscope FAT Tänikon, CH-8356 Ettenhausen / Switzerland