Dear Bioconductor-listers, I want to reperfrom a poisson distribution test that was presented in a recent-published biological research paper (Plant Physiology 2008, vol 148, pp. 1189-1200). That test is about the occurrence number of a kind of gene in separate chromosomes. For instance: The observed gene number in chromosome A is 36. The expected gene number in chromosome A is 30. Then, the authors got a probability 0.137 by distribution test on this trial. In this test, a Poisson distribution was used to determine the significance of the gene distribution. Questions: How can I reperform this test in R? Thank you in advance. Mao Jian-Feng Institue of Botany, CAS, China [[alternative HTML version deleted]]

Dear Mao, I don't know about the particular setting but here's a simple approach: > ppois(q=35,lambda=30, lower=F) [1] 0.1573835 gives the probability of observing 36 or more events from a Poisson distributed random variable with mean 30 (aka expected number of genes). Does not give you the exact figure (0.137) though. Best Michael Am 28.07.2009 um 12:06 schrieb Mao Jianfeng: > Dear Bioconductor-listers, > > I want to reperfrom a poisson distribution test that was presented > in a > recent-published biological research paper (Plant Physiology 2008, > vol 148, > pp. 1189-1200). That test is about the occurrence number of a kind > of gene > in separate chromosomes. > > For instance: > > The observed gene number in chromosome A is 36. > The expected gene number in chromosome A is 30. > > Then, the authors got a probability 0.137 by distribution test on this > trial. In this test, a Poisson distribution was used to determine the > significance of the gene distribution. > > Questions: > > How can I reperform this test in R? > > Thank you in advance. > > Mao Jian-Feng > Institue of Botany, > CAS, China > > [[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 Michael Dondrup, Ph.D. Bergen Center for Computational Science Computational Biology Unit Unifob AS - Thorm?hlensgate 55, N-5008 Bergen, Norway