On 20/04/11 22:25, vioravis wrote: > This should work!! > > rmse<-function (x){ > dquared<-x^2 > sum1<-sum(x^2,na.rm=TRUE) > rmse<-sqrt((1/length(x))*sum1) > rmse} Shouldn't the divisor be the number of non-missing values in x? Rather than the length of x? (Like, e.g. sum(!is.na(x)) ?) cheers, Rolf Turner