Hi, I got the following error using GSA package gsa<-GSA(x=X,y=as.vector(rbind(1:15,-c(1:15))), resp.type="Two class paired", genenames=thesymb, geneset=LZ$genesets) Error in GSA.func(x, y, genesets = genesets, genenames = genenames, method = method, : could not find function "paired.ttest.func" In fact ?paired.ttest.func give the same error but not for ? quantitative.func,?multiclass.func best Mayte