[R] glmmBUGS: logistic regression on proportional data

[David Winsemius]

Installing the glmmBUGS package and a bit of experimentation produces  
this minor modification of your code that seems to run without error.  
It's back to you to see if the output is sensible.

library(glmmBUGS)
Newdat<-data.frame(Newtree=rep(1:3, each=20), Newsect=rep(c("a","b"),
each=10), Newdist=rep(1:5, 2),
                  y=rpois(60,2), tot=rep(c(14,12,10,8,6), 12))

yseed<-cbind(Newdat$y, Newdat$tot)

mod<-glmmBUGS(y/tot~Newsect + Newdist, effects="Newtree",
family="binomial", data=Newdat)

I am guessing that the interpreter was looking for a variable yseed  
within Newdat and not finding it. It, however, is able to "see" y and  
tot within Newdat. Also appears that using cbind(y, tot) on the LHS of  
hte formula will avoid the error you were getting.

-- 
David Winsemius
Heritage Labs

On Feb 8, 2009, at 8:29 AM, John Poulsen wrote:

> Hello,
>
> I am trying to run a logistic regression with random effects on  
> proportional data in glmmBUGS.  I am a newcomer to this package, and  
> wondered if anyone could help me specify the model correctly.
> I am trying to specify the response variable, /yseed/, as # of  
> successes out of total observations... but I suspect that given the  
> error below, that is not correct.  Also, Newsect should be a factor,  
> whereas Newdist is continuous.
>
> Thanks,
> John
>
>
> Newdat<-data.frame(Newtree=rep(1:3, each=20),  
> Newsect=rep(c("a","b"), each=10), Newdist=rep(1:5, 2),
>                  y=rpois(60,2), tot=rep(c(14,12,10,8,6), 12))
>
> yseed<-cbind(Newdat$y, Newdat$tot)
>
> mod<-glmmBUGS(yseed~Newsect + Newdist, effects="Newtree",  
> family="binomial", data=Newdat)
>
> Error in `[.data.frame`(data, , response, drop = FALSE) :
> undefined columns selected
>
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