Hi, i was looking into the documentation for the rma() function in affy() package, and was trying to figure out how exactly the background normalization is done. I read all three papers cited in the rma() documentation, but the most detailed explanation i could find was in Irizary et al., 2003, where they state that they compute
B(PM_{ijn}) = E[s_{ijn} | PM_{ijn}] where s_{ijn} is assumed to be exponential, and bg_{ijn} is normal. I still don't understand what value is being computed here, neither am i clear on what the correction looks like. i.e. if s_{ijn} is an exponentially-distributed random variable, how is bg_{ijn} fit into this? thanks! [[alternative HTML version deleted]] ______________________________________________ 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.