[BioC] Help on interpreting PPDE values

Kartik Pappu kartik.pappu at gmail.com
Tue Sep 19 02:10:35 CEST 2006


Hi all,

I am statistically deficient biologist trying to interpret the results
of differential expression analysis that I ran on Cyber T.  My
question is:

I compared 3 experimental samples to 3 controls and obtained a list of
genes their corresponding P values and their associated Posterior
Probabailities of differential expression.  Given these values how can
I find out how many false positives I will obtain by choosing an
arbitrary threshold for the p values and the PPDE values.

So for example I set the cut off for p values at 0.01 and PPDE > .95.
The p value cut off gives me 145 genes.  How many of these 145 genes
can I expect to be false positives given a PPDE>.95.

I hope this question makes sense.

Thanks
Kartik



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