Hi, I need a precision about columm "size" in out of hyperGtest ( Gostat package) In https://stat.ethz.ch/pipermail/bioconductor/2006-December/015346.html we can read: "The "Size" column is the number of genes annotated at the given GO term (where genes are restricted to the defined gene universe)" Hence, for a given Term and given platform, we must have a constant number. I explain: first set data : A contains 687 probesets I practise a hyperGotest: This is an extract from the result: GOBPID Pvalue OddsRatio ExpCount Count Size Term 36 GO:0008283 0.0180640706 1.913970 8.20236088 15 266 cell proliferation If I inderstand well: 266 probesets on affy HGU133.2.plus are annotated "cell proliferation" Then, I practise the same analysis on a second set (B) , inclusive of A : 414 probesets result : GOBPID Pvalue OddsRatio ExpCount Count Size Term 20 GO:0008283 0.008295992 1.765957 14.97834828 25 745 cell proliferation Here, that's mean that 745 probesets are annotated "cell proliferation" Why the number of size for the same term is not the same? Moreover, B being inclusive of A , the 25 probesets annotated "cell proliferation " , discovered in B analysis are reduced to 15 probesets in A analysis. Normally, in A analysis, I should have at least 25 probesets annotated "cell proleferation". Why didn't I find at least 25 probesets in A analysis ? Thanks Greg > sessionInfo() R version 2.8.1 (2008-12-22) i386-pc-mingw32 locale: LC_COLLATE=French_Canada.1252;LC_CTYPE=French_Canada.1252;LC_MONETARY= French_Canada.1252;LC_NUMERIC=C;LC_TIME=French_Canada.1252 attached base packages: [1] splines tools stats graphics grDevices utils datasets methods base other attached packages: [1] GOstats_2.8.0 Category_2.8.4 genefilter_1.22.0 survival_2.34-1 RBGL_1.18.0 annotate_1.20.1 xtable_1.5-4 [8] graph_1.20.0 GO.db_2.2.5 hgu133plus2.db_2.2.5 RSQLite_0.7-1 DBI_0.2-4 AnnotationDbi_1.4.3 Biobase_2.2.2 loaded via a namespace (and not attached): [1] cluster_1.11.11 GSEABase_1.4.0 XML_1.99-0 [[alternative HTML version deleted]]

Hi Greg, I am a little confused by your description of what you did. After peering at your explanation, I am still not completely certain that I understand what your question is. But, there is a nice description of how the gene universe can affect the number of things you find in the GOstats vignette titled "Hypergeometric Tests Using GOstats". Perhaps this can help you? http://www.bioconductor.org/packages/devel/bioc/html/GOstats.html Marc gregory voisin wrote: > Hi, > > I need a precision about columm "size" in out of hyperGtest ( Gostat package) > > In https://stat.ethz.ch/pipermail/bioconductor/2006-December/015346.html > we can read: "The "Size" column is the number of genes annotated at the given GO > term (where genes are restricted to the defined gene universe)" > Hence, for a given Term and given platform, we must have a constant number. > > I explain: > first set data : A contains 687 probesets > I practise a hyperGotest: > This is an extract from the result: > GOBPID Pvalue OddsRatio ExpCount Count Size Term > > 36 GO:0008283 0.0180640706 1.913970 8.20236088 15 266 cell proliferation > > If I inderstand well: 266 probesets on affy HGU133.2.plus are annotated "cell proliferation" > > > Then, > > I practise the same analysis on a second set (B) , inclusive of A : 414 probesets > > result : > GOBPID Pvalue OddsRatio ExpCount Count Size Term > > 20 GO:0008283 0.008295992 1.765957 14.97834828 25 745 cell proliferation > > Here, that's mean that 745 probesets are annotated "cell proliferation" > > > > Why the number of size for the same term is not the same? > > Moreover, B being inclusive of A , the 25 probesets annotated "cell proliferation " , discovered in B analysis are reduced to 15 probesets in A analysis. Normally, in A analysis, I should have at least 25 probesets annotated "cell proleferation". > > Why didn't I find at least 25 probesets in A analysis ? > > > > > Thanks > Greg > > > >> sessionInfo() >> > R version 2.8.1 (2008-12-22) > i386-pc-mingw32 > > locale: > LC_COLLATE=French_Canada.1252;LC_CTYPE=French_Canada.1252;LC_MONETAR Y=French_Canada.1252;LC_NUMERIC=C;LC_TIME=French_Canada.1252 > > attached base packages: > [1] splines tools stats graphics grDevices utils datasets methods base > > other attached packages: > [1] GOstats_2.8.0 Category_2.8.4 genefilter_1.22.0 survival_2.34-1 RBGL_1.18.0 annotate_1.20.1 xtable_1.5-4 > [8] graph_1.20.0 GO.db_2.2.5 hgu133plus2.db_2.2.5 RSQLite_0.7-1 DBI_0.2-4 AnnotationDbi_1.4.3 Biobase_2.2.2 > > loaded via a namespace (and not attached): > [1] cluster_1.11.11 GSEABase_1.4.0 XML_1.99-0 > > > > [[alternative HTML version deleted]] > > _______________________________________________ > Bioconductor mailing list > Bioconductor at stat.math.ethz.ch > https://stat.ethz.ch/mailman/listinfo/bioconductor > Search the archives: http://news.gmane.org/gmane.science.biology.informatics.conductor > >