Before I receive a barrage of 'try looking in the help file' messages, I have and to no avail. For a new user of R I would like to point out that in order to be able to use the help files/manuals effectively one must know the correct question and that only comes with using R! Could someone please direct me to why I keep getting the following error message "Error: subscript out of bounds" when the following code is run z.score<-function (group) { for (t in levels(group$Country)) { # this will give t countries y<-subset(group,factor(Country)==t) #particular analyte over all countries equal to y #calculate overall huber mean and sigma for a particular analyte over all countries ov.mu<-hubers(group$X)$mu ov.sigma<-hubers(group$X)$s #define arrays #p.mu<-array() #p.sigma<-array() #z.value<-array() #calculate huber mean and sigma for given analyte (defined by group) by selected country (y) p.mu<-hubers(y$X)$mu #p.sigma<-hubers(y$X)$s #calculate z score for particular analyte:country combination #z.value<-as.vector((p.mu[t]-ov.mu)/ov.sigma) } #data<-list(mean=ov.mu,sd=ov.sigma) return(p.mu) } # group entered as group=subset(sub2, factor(Analyte)=="Cholesterol") for example # # # # # Please ignore the commented out lines, these were put in for my own use. The code gave the same error message with them removed. Thankyou for your help Mike Griffiths Michael Griffiths, Ph.D. Chemometrician Training, Quality and Statistics Group LGC Limited Queens Road Teddington Middlesex, TW11 0LY, UK Tel: +44 (0)20 8943 7352 Fax: +44 (0)20 8943 2767 e-mail: michael.griffiths at lgc.co.uk ******************************************************************* This email and any attachments are confidential. Any use, co...{{dropped}}