Hello. I am fitting a repeated measures model using the mixed model function of R (lme). However, the hierarchical structure is complicated. Each individual sheep is measured a number of times (once per year) over its life (ranging from once to 12 consecutive years). However, this longitudinal study involves many different cohorts and so many different individuals (of different ages) are measured each year. Therefore, individuals measured in the same year are not independent. A typical data set might look like this:
Ind age year mass 1 1 1984 2.3 1 2 1985 4.3 1 3 1986 5.5 ... 2 1 1985 3.3 2 2 1986 4.1 ... Can someone explain how to specify this in the random part of the model specification in the lme function of R? If I were to ignore the "year" effect, I would specify: lme(mass~age, random=age|ind) Bill Shipley Associate Editor, Ecology North American Editor, Annals of Botany Département de biologie, Université de Sherbrooke, Sherbrooke (Québec) J1K 2R1 CANADA [EMAIL PROTECTED] <http://callisto.si.usherb.ca:8080/bshipley/> http://callisto.si.usherb.ca:8080/bshipley/ [[alternative HTML version deleted]] ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
