For a data set dat with variable 'case', it follows sam.rate=0.9 n.ctrl<-nrow(dat[dat$case==0,]) sam.ctrl<-dat[sample(row.names(dat[dat$case==0],n.ctrl*sam.rate,replace=F),] rbind(dat[dat$case==1,],sam.ctrl)
Weidong Gu On Mon, Oct 31, 2011 at 1:54 PM, loubna ibn majdoub hassani <loubn...@gmail.com> wrote: > Hi > I have an umbalanced data set where I want to predict a binary variable Y. > I want to do an under sampling by keeping all the 1 and taking just some of > the 0 such as I'll have 90% of 0 and 10% of 1. > Can u help me do that > Thank u > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
