Hi, I would like to attach my answer although this question has been posted here for more than a year. I believe some people may meet the same problem.
I use sampling package to do the stratified sampling as well, using strata() function. And everything goes well before I add another library: Hmisc. I need this library to handling some pre-process on data. After trouble shooting for a long time, believe me it's miserable, I finally found: There's conflict between Hmisc and sampling packages. I suggest if strata pops unusual error like this, you should check if your libraries are incompatible with each other. Hope this helpful to you:) -- View this message in context: http://r.789695.n4.nabble.com/package-sampling-tp3083392p4268215.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
