[BioC] power calculation

[kfbargad at ehu.es]

Dear list,

A collaborator has asked if it is possible to calculate a general 
power value of the experiment once it has been done. I believe power 
is set prior to designing the experiment, as the same time as defining 
significance level, so that the sample size can be estimated. I think 
I can calculate the power for individual genes that have come out as 
d.e. using their group means and SD, the number of samples available 
and the significance value, but I am not sure this is actually useful 
but is it possible to calculate a, say, "general experimental power 
value" given the number of replicates per condition is already set?

Hope I make myself understandable. Thanks in advance,

David