Hi Everybody Its me again. I have been able to sample using SRS and stratified sampling when i have predefined groups as follows: Hypermarket <- matrix(rnorm(100, mean=50000, sd=5000)) Supermarket <- matrix(rnorm(400, mean=34000, sd=3000)) Minimarket <- matrix(rnorm(1000, mean=10000,sd=2000)) Cornershop <- matrix(rnorm(1500, mean=2500, sd=500)) Spazashop <- matrix(rnorm(2000, mean=1000, sd=250)) dat=data.frame(type=c(rep("Hypermarket",100), rep("Supermarket",400), rep("Minimarket",1000),rep("Cornershop",1500), rep("Spazashop",2000)), value=c(Hypermarket, Supermarket, Minimarket, Cornershop,Spazashop)) dat names(dat)=c("type","value") #Number of observations for each outlet type in a population dat$type <- factor(dat$type, levels = c("Hypermarket","Supermarket","Minimarket","Cornershop","Spazashop")) (stratas<-data.frame(table(dat$type))) ##sampling and proportional allocation as.matrix(table(dat$type)) s=strata(dat,c("type"),size=c(20,80,200,300,400), method="srswor") dat.strat<-getdata(dat,s) dat.strat Now i want to use the rectangular method to determine strata boundaries, thenfor the allocation use Neyman, so please help me achieve this. [[alternative HTML version deleted]]