Hi Eszter, These are all in the "base" package .. Please try ... ?sapply ?diag ?sqrt for the standardization ... invTotal<-t(1/sapply(mydataset,sum,na.rm=T)) szorzo<-diag(as.vector(invTotal),length(invTotal)) szorzo%*%t(mydataset) Szia, Manuel Dear Colleagues, It is Eszter Illy??s from Hungary. I just have started to use R yesterday, so I am a real beginner (but I could run some PCOA and managed to transpose a dataframe). No I have a problem that I would like to standardize my datafile with the row totals and than make an arcsin squareroot transformation. How can I do that? In which package shall I look for and for what option? Thank you very much, have a nice day Eszter _______________________________________________________________________ K??ptipp! J??tssz a T-Online k??pkeres??j??vel! Ha el??g ??gyes ??s gyors vagy, felker??lhetsz a dics??s??gt??bl??ra... www.t-online.hu ______________________________________________ R-help at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html