Hi all, I'm working on a seemingly trivial problem that I can't figure out how to implement in R. I'd be most grateful for any help here.
I want to do the following: first, randomly assign each of n units to one of g groups of size n/g. Then, randomly re-assign each of the n units to a different group (i.e., same as the first step, but the unit can't be assigned to a group to which it's already belonged). Then repeat this step until each unit has at some point been assigned to every group. More concretely, say I have 60 units and 3 groups into which to divide the units. I could first do something like: group1<-sample(1:60,20) group2<-sample(setdiff(1:60,group1),20) group3<-sample(setdiff(1:60,c(group1,group2)),20) But then how to randomly re-assign group membership such that all units are assured a different group assignment in the second "wave" of grouping? Just narrowing the sampling pool to those units that weren't previously assigned to a given group won't work (consider the case where groups 1 and 2 swap units: in the second wave, there would be no units to assign to group 3 as all the remaining units had already been in group 3 in the first wave). Most grateful for any assistance, David ______________________________________________ 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.
