HI, I want to use gcrma background correction in expresso function (so I can use other normalisation methods and different summary methods). However I seem to get errors, can someone please check my R codes below: Also, I don't know where to find/search the archives of other FAQ for bioconductor Regards Anthony cs.data<-ReadAffy() gcrma.mle<-bg.correct.gcrma(cs.data,gcgroup=getGroupInfo(cs.data),esti mate="mle") gcrma.eb<-bg.correct.gcrma(cs.data,gcgroup=getGroupInfo(cs.data),estim ate="eb") eset<-expresso(gcrma.eb,bg.correct=FALSE, normalize.method="loess",pmcorrect.method="pmonly",summary.method="med ianpolish") -- ______________________________________________ Anthony Bosco - Cell Biology Research Assistant Institute for Child Health Research (Company Limited by Guarantee ACN 009 278 755) Subiaco, Western Australia, 6008 Ph 61 8 9489 , Fax 61 8 9489 7700 email anthonyb@ichr.uwa.edu.au