Greetings UseRs, Pls advise if there is a way to write a func that can be supplied to aggregate to compute weighted MeanAbsolute Dev (MAD). I am having trouble passing the correct weights from each group level and cannot see the code behind aggregate. But maybe 'aggregate' is not the best way to do that.
> m1 <- > aggregate(pool[,c("SMM")],by=list(time=pool$ym),weighted.mean,w=pool$wght) Error in weighted.mean.default(X[[1L]], ...) : 'x' and 'w' must have the same length Apparently the grouping does not work on the additional argument. I am using weighted mean here just to be explicit and avoid supplying a custom function gor weighted MAD, which is not difficult to write by itself. It's making it work with aggreagte that is the problem. > aggregate function (x, ...) UseMethod("aggregate") <environment: namespace:stats> Does not show anything... Stephen B ______________________________________________ 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.