Check the package doBy as well (pretty handy for analysis of grouped data).
library(doBy) summaryBy(PM~ID,data=d,FUN=median) HTH, -Girish -- View this message in context: http://n4.nabble.com/median-of-grouped-data-tp1311971p1312386.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
