"lme" question

["Gupta, Pankaj*" <GuptaP@cder.fda.gov>]

 

         Dear users,

I am using 'lme' to fit a linear mixed effects model as follows: 

 

lme(response~time,data="">

 

The plots of the random effects vs. covariates show that the intercept increases (almost as a straight line) with body weight. I thus wish to to test whether bw can be included as a covariate in the model.

 

I would really appreciate if someone could help me out with the procedure  for  doing so.

 

Thanks

 

Pankaj