[BioC] "Size" in summary() of "hyperGTest()
Seth Falcon
seth at userprimary.net
Thu Feb 19 19:30:51 CET 2009
* On 2009-02-19 at 00:54 +0000 Sergei Manakov wrote:
> Thanks for your reply. You are right, indeed I have used conditional =
> TRUE, and that is the reason why "Size" differs. Sorry about that, I
> should have guessed that myself. However, I find the description of
> the option "conditional" rather short in the Vignette. Could you
> please maybe just in a few sentences explain what it exactly it does?
> That would be very helpful.
The help page for GOstats::hyperGTest has some detail:
When 'conditional(p) == TRUE', the 'hyperGTest' function uses the
structure of the GO graph to estimate for each term whether or not
there is evidence beyond that which is provided by the term's
children to call the term in question statistically
overrepresented.
The algorithm conditions on all child terms that are themselves
significant at the specified p-value cutoff. Given a subgraph of
one of the three GO ontologies, the terms with no child categories
are tested first. Next the nodes whose children have already been
tested are tested. If any of a given node's children tested
significant, the appropriate conditioning is performed.
You might also find some of the discussion in this paper helpful:
> citation("GOstats")
To cite GOstats in publications use:
S Falcon and R Gentleman. Using GOstats to test gene lists for GO
term association. Bioinformatics, 23(2):257-8, 2007.
+ seth
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