Hi I've been reading the help for by and aggregate but can't get my head round how to do this.
I have a data frame - the first three columns are replicate measurements, then the next 3 are replicates etc up to 36 (so 12 variables with 3 replicate measurements each). I want to compute the mean for each of the 12 variables, so that, for each row, I have 12 means. A grouping variable across columns can easily be created by rep(1:12,each=3), but I can't figure out which function to use to get R to calculate the means I want. Thanks in advance Mick ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
