At 03:17 AM 24/08/2003, Christian Probst wrote: ... deleted stuff >A finally question, as I don?t know your opinion about. > > I am not a statistician. I would like to know if my point "it is better > to have more time points per experiment than more replicates per time > point and less time points per experiments" is a good one. > >Because I am "replicating" my data, but collecting another kind of info >(temporal info) also. Well, collecting more time points isn't replication. You're asking whether it is better to have more time points *instead* of having replication. As always, what's a good design depends on the what questions you want to answer and what analysis you're going to do. If you have lots of time points so that changes between consecutive time points will be small, then more time points might be better than replication. If you're just going to compare expression levels without any formal statistical analysis, or you're going to use an exploratory or unsupervised data technique like cluster anlysis, then again more time points might be better. If however you want to use statistical inferential techniques to assess differential expression, and your time points are such that genes may substantially change their expression levels between consecutive times, then I cannot see any alternative to having true replication. Regards Gordon >Anyway, > >Thanks for your patience. It is always a pleasure to read your comments in >the BioC list >Christian