[BioC] compare expression measures

Sean Davis sdavis2 at mail.nih.gov
Wed Jan 4 22:25:06 CET 2006

On 1/4/06 2:57 PM, "Mohammad Esad-Djou" <shahrgol at web.de> wrote:

> Hello, 
> I wants to compare expression measures, which was computed with MAS and RMA.
> But I noticed that the expression-values are very different.
> e.g.: Expt1_R1.CEL: Gen: 1007_s_at
> RMA: 8,06941
> MAS: 236,16853028
> 1. How can I interpret this difference?

MAS is not in log2 units.  RMA is in log2 units.

> 2. And which mathematical methods for comparison between preprocessing can I
> use? 

One place to look would be the affycomp package.  However, you might want to
look at the literature a bit before going too far; some of these comparisons
have been done already with tightly controlled experiments.

Hope that was what you were asking....

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