NLME Covariates
I am foggy on this myself, but I *think* it is inferred from the grouping structure in the call to (n)lme or in the groupedData data structure. Have a look at ?groupedData in R for more details. ap ---------------------------------------------------------------------- Andrew J Perrin - http://www.unc.edu/~aperrin Assistant Professor of Sociology, U of North Carolina, Chapel Hill clists at perrin.socsci.unc.edu * andrew_perrin (at) unc.edu
On Wed, 25 Jun 2003, Harold Doran wrote:
Dear list In HLM, one can specify a covariate at one of the "levels". For example, if the data structure are repeated observations nested within students nested within schools, school size might be a covariate that is used at level 3, but not at the other levels. In HLM this is rather easy to do. However, how can one specify a covariate in R for only one of the levels? I have a sample data set with the structure as described above. I fit the unconditional model in R as model1<-lme(math~year, random=~year|schoolid/childid, data=datafile) Now, if I want to enter "female" as a covariate at level 2 only, how might I modify the code to accomplish this? ------ Harold C. Doran Director of Research and Evaluation New American Schools 675 N. Washington Street, Suite 220 Alexandria, Virginia 22314 703.647.1628 <http://www.edperform.net/> [[alternative HTML version deleted]]
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