I'm trying to fit a mixed-effects model of the form Y = a + bX + cZ + e where X are fixed effects and Z are random. i.e., c is a vector of random coefficients with mean 0. There is no "grouping" variable such as would be used with longitudinal data. Can the nlme package handle this sort of thing? Although it is a simpler model than would be used with grouped data, I can't seem to convince lme() to fit it. It seems to want a grouping variable and I can't persuade it that there is no such thing. Any help would be appreciated. Rob __________________________________________________ Associate Professor Rob J Hyndman Department of Econometrics & Business Statistics, Monash University, VIC 3800, Australia http://www-personal.buseco.monash.edu.au/~hyndman/ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Rob Hyndman <Rob.Hyndman at buseco.monash.edu.au> writes:> I'm trying to fit a mixed-effects model of the form > Y = a + bX + cZ + e > where X are fixed effects and Z are random. i.e., c is a vector of > random coefficients with mean 0. There is no "grouping" variable such as > would be used with longitudinal data. > > Can the nlme package handle this sort of thing? Although it is a simpler > model than would be used with grouped data, I can't seem to convince > lme() to fit it. It seems to want a grouping variable and I can't > persuade it that there is no such thing. > > Any help would be appreciated.It's been a while since I played around with this, but as far as I remember there is no requirement that the grouping variable has more than one group... -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._