(sorry if this is a multiple post) Dear Bioc community, I have a little question about combining p-values with stouffers method. One of the conditions for combining p-values is that each test be considered as independent. If I was interested in a group of say, 10 genes and I wanted to know if, as a group, they were significantly over or under expressed, would it be correct to combine the p-values (calculated from a series of microarrays) for each individual gene using stouffers method to be able to conclude that this group of genes is differentially expressed ? Thanks, william. ____________________________________________________________ ente http://mail.yahoo.fr