Entering edit mode
8.9 years ago
Shamim Sarhadi
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220
Hi guys
I have a dataset with 100 sample and 54000 feature,I used to think that if I filter those of probIDs with little variation, I can reduce the number of features and then in multiple testing with limma it gives me fewer errors and finally fewer noises, but now I found that if I use genefilter package of bioconductor, It changes the the distribution of variance and will interfere with limma package
Let me know if I am mistaken and tell me if there are other options except genefiltering package
TNX
Hint: filter after the testing, just make sure to not filter on something linked to the test.
But I want to filter non-informative probID before the test(those with little variation or those with not express in most of samples ) but now the problem is that the limma in it's vintage says that some filtering method have conflict with limma as I said before !!
Why are you fixated on filtering before testing? You can just readjust the p-values after filtering post-testing and this is the recommended method. If you just did what I suggested then limma would work fine and you would get good results.
BTW, do make sure that your p-values are uniformly distributed over variance if you're going to filter by that. Whatever you filter by MUST not correlate with the test or you're p-hacking.
Thank you Devon
I do not insist on filtering before testing !!! I just thought it gives me a better result, It seems your suggestion is more reasonable
tnx again