[BioC] Expression values using RMA

[Ben Bolstad]

RMA expression measures are log base 2 scale (as given both via rma()
and expresso()). If you wish to have non transformed signals use take 2
to the power of your expression measures.

ie something like

2^(exprs(eset))






On Wed, 2003-05-21 at 03:33, Martino Barenco wrote:
> Hi,
> 
> Using the hard-coded version of rma in the library affy, I find the 
> expression values to be on a quite narrow range in relative terms 
> (range=(3.5,14)). With other methods (eg mas, dchip), the signals span 
> about four order of magnitude. Does this mean the expressions output by 
> rma are log-tranformed? if so, which basis should be used to recover 
> non-transformed signals?
> 
> Thank you
> 
> Martino
> ---------------------------------------
> Martino Barenco
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-- 
Ben Bolstad <bolstad at stat.berkeley.edu>