MASS fitdistr with plyr or data.table?
require(MASS) out <- with(weib.test.too, tapply(wind_speed, site, function(x) fitdistr(x, 'weibull'))) estimates <- t(sapply(out, "[[", 1)) SDs <- t(sapply(out, "[[", 2)) estimates SDs HTH, Jorge
That'll do nicely and is much more elegant than my current method. I was sure there would be some fancy one liner from plyr though! Thanks a bunch, Justin