search for: phyper

Hi, I am attempting to use phyper to test the significance of two overlapping lists. I keep getting a zero and wondered if that was determining non-significance of my overlap or a p-value too small to calculate? overlap = 524 lista = 2784 totalpop = 54675 listb = 1296 phyper(overlap, lista, totalpop, listb,lower.tail = FALSE, log...

...out the hypergeomteric distribution. Example 1: I have a universe of 6187 objects, and 164 have a particular attribute, therefore 6187-164 do not have that attribute. I sample 249 of those objects, and find that 19 have that attribute. I get a p-value here (looking at just over-representation): phyper(19, 164, 6187-164, 249, lower.tail=FALSE) [1] 7.816235e-06 Example 2: I have a universe of 6187 objects, and 12 have a particular attribute, therefore 6187-12 do not have that attribute. I sample 249 of those objects, and find that 4 have that attribute. I get a p-value here (looking at just ove...

Dear R-users, In R 2.5.1 on Windows XP, SP2 the call to phyper(0,0,74,3,lower.tail=FALSE) returns -4.195862e-17. This does not happen with R2.5.1 on Linux, 0 is returned. Is this a bug (and should be reported as such), since phyper should not return negative values, or is this considered as one of the annoyances of finite precision arithmetic. I tend to think...

Full_Name: Morten Welinder Version: snapshot OS: Submission from: (NULL) (65.213.85.218) Time to kick phyper's tires... The current version has very serious cancellation issues. For example, if you ask for a small right-tail you are likely to get total cancellation. For example phyper(59, 150, 150, 60, FALSE, FALSE) gives 6.372680161e-14. The right answer is dhyper(0, 150, 150, 60, FALSE) which is...

...ulative hypergeometric probabilities (i.e. the summation of probabilities given by equation 3.1 of Seber, 1973)." The reference is to G.A.F. Seber's book, The Estimation of Animal Abundance. I went to equation 3.1 and wrote a small function to sum its probabilities, modeled after phyper() and taking the arguments in the same order (the names have changed to suit the archaeological situation): > seber <- function(p,l,n,r) > { > y <- 0 > for (x in 0:p) > y <- y + exp(lchoose(l,x) + lchoose(n-l,r-x) - lchoose(n,r)) > y > } Whe...

Full_Name: Utz J. Pape Version: 2.2.0 OS: linux Submission from: (NULL) (141.14.23.12) If I use phyper and set parameter x equal to k (meaning that all balls I draw are white) phyper returns 1 which is not (always) correct: pape at xxx:~> R2.2.0 --vanilla R : Copyright 2005, The R Foundation for Statistical Computing Version 2.2.0 (2005-10-06 r35749) ISBN 3-900051-07-0 R is free software and...

Hello, I've come across the following situation in R-1.8.1 (compile + running under RedHat 7.1): > phyper(24, 514, 5961-514, 53, lower.tail=T) [1] 1 > phyper(24, 514, 5961-514, 53, lower.tail=F) [1] -1.037310e-11 I'd expect the later to be 0 or some very small positive number. Is this a number under-flow of the calculation? Do you think I'm safe if I just set the result to 0 in these cases?...

Dear R Users, I employed the phyper() function to estimate the likelihood that the number of genes overlapping between 2 different lists of genes is due to chance. This appears to work appropriately. Now i want to try this with 3 lists of genes which phyper() does not appear to support. Some googling suggests i can utilize the M...

Dear list, I have performed several tests for the hypergeometric distribution using phyper() for some gene annotation categories as follows >phyper(26,830,31042,337, lower.tail=F) >phyper(16,387,31042,337, lower.tail=F) . . . I am only running some selected categories but I would like to correct this value for multiple testing since I have 3121 possible tests according to 31...

Last night I sent the bug report below to r-help. I have since then looked at dhyper.c and found: if (NR < 0 || NB < 0 || n <= 0 || n > N) DOMAIN_ERROR; I changed 'n <= 0' to 'n < 0' and then dhyper worked as I wanted. Am I introducing some potentially dangerous behaviour by this change? Goran

In both versions of R to which I currently have access (R-0.16.1 and R-0.61.1), "phyper" stops returning correct cumulative probabilities as the parameters of the hypergeometric distribution get large. For example, when N1=1345, N2=1055, and n=1330, phyper returns either 0 or 1, and nothing in between. Looking at phyper.c, it's clear what's happening. First a term (calle...

Hi all, I have tried to compute a p-value for a hypergeometric distribution as: dhyper(x,k,l,n) + phyper(x,k,l,n,lower.tail=FALSE) and sometimes obtained negative values. Do you know if it is because a round error or am I doing something wrong? Thanks in advance, Aurora

Dear R team, I have a simple question. I tried this command: phyper(17,449,19551,181, FALSE) [1] 1.47295e-07 and then I tried this command: (fisher.test(matrix(c(17,449,181,19551),2,2), alternative='greater'))$p.value [1] 3.693347e-06 Shouldn't be identical the results of the two commands ? What is the difference ? Thx a lot -- View this message in...

...with the parameters m=45000,n=5000 and k=600 I use the R-command > qhyper(0.95,45000,5000,600). The value obtained is 600. However, the true value is 552. The latter can be obtained for example by calling the corresponding distribution function with the R commands > x<-540:580 > phyper(x,45000,5000,600) The value 552 is obtained also by the usual normal approximation. Overall, it seems that R produces errors when calling qhyper(p,m,n,k) for large values of the parametes m,n or k. Sincerely L. Baringhaus -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-....

Hi, I need to run a Fisher's exact test on thousands of 2x2 contingency tables, and repeat this process several thousand times (this is a part of the permutation test for a genome-wide association study). How can I run this process most efficiently? Is there any way to optimize R code? I have my data in a 2x2xN array (N ~ 5 K; eventually N will be ~ 500 K), and use apply inside the loop:

> Dear R-users! > > I am using R 1.0.0 and Windows NT 4.0. > Suppose I have a population of N=100 subjects, a binomial variable and a random sample of n=20 subjects from my population, giving 15 "successes". I am interested in obtaining a confidence interval for the proportion of "successes" in my population. In R, I can use > library(ctest) >

Full_Name: Anja von Heydebreck Version: 1.9.1 OS: Linux Submission from: (NULL) (155.250.128.25) I obtained a negative p-value from the fisher.test() function: > fisher.test(matrix(c(14576,3023,89,68),2), alternative="g")$p.value [1] -8.426593e-13 With R 1.8.1, I got a p-value of -6.239231e-12 for this example. Anja von Heydebreck

Hi Developers, The alpha, compiles successfully, but it is failing make check-all (on two seperate machines, both FreeBSD 6.1). Here is the version string: platform i386-unknown-freebsd6.1 arch i386 os freebsd6.1 system i386, freebsd6.1 status alpha major 2 minor 3.0 year 2006 month 03 day 27 svn rev

...geom.o dhyper.o dlnorm.o dlogis.o dnbeta.o dnbinom.o dnchisq.o dnf.o dnorm.o dnt.o dpois.o dt.o dunif.o dweibull.o fmax2.o fmin2.o ftrunc.o gamma.o gamma_cody.o i1mach.o imax2.o imin2.o lbeta.o lgamma.o lgammacor.o mlutils.o pbeta.o pbinom.o pcauchy.o pchisq.o pexp.o pf.o pgamma.o pgeom.o phyper.o plnorm.o plogis.o pnbeta.o pnbinom.o pnchisq.o pnf.o pnmath.o pnorm.o pnt.o polygamma.o ppois.o pt.o ptukey.o punif.o pweibull.o qbeta.o qbinom.o qcauchy.o qchisq.o qexp.o qf.o qgamma.o qgeom.o qhyper.o qlnorm.o qlogis.o qnbeta.o qnbinom.o qnchisq.o qnf.o qnorm.o qnt.o qpois.o qt.o qtukey...

Hi, set.seed(45) test1<-data.frame(columnA=rnorm(7,45),columnB=rnorm(7,10)) #used an example probably similar to your actual data apply(test1,2,function(x) sprintf("%.1f",median(x))) #columnA columnB # "44.5"? "10.2" par(mfrow=c(1,2)) lapply(test1,function(x) {b<-