Check the results before next move...

Just found out the maQualityPlots() produced several diagnostic plots including both MA plts before and after normalization.. Orz Orz Orz Orz Orz..

Well.. but from this "mistake" we did learn things including how to extract subsets of data from an object, and to get MA plots after normalization.

Next, I would try to generate diagnostic plots without maQualityPlots()...