[R-sig-ME] How to extract num. of observations and groups used in a mixed model using gee package

[Ben Bolker]

david oseguera montiel <oseguera.david at ...> writes:

> 
> I meant the grouping factor in the model indicated by id. From gee 
> documentation 'id = a vector which identifies the clusters..'. So in the 
> warpbreaks data set, id = wool has 54 obs, in two clusters (groups).

 [snip]

> >> David,
> >> Thank you very much. Number of observations solved, but I am still 
> >> missing how to find out the number of groups used. In the warpbreaks 
> >> data set these are 2. Any ideas. Thank you.
> >>
> > I must be unclear what you mean by "number of groups".


 Didn't Chuck Cleland's answer work, i.e. length(unique(model$id)) ... ?