similar to: Difference Between R: wilcox.test and STATA: signrank

I took some time and liberty and tried to improve existing implementation of SignRank functions in R. (dsignrank, ...) As I have seen they've been based on csignrank. So I modified csignrank and, I believe, improved calculation time and memory efficiency. The idea is basically the same. I use the same recursion as original author used with one slight modification. I am generating Wilcoxon

There is a fairly new bug in wilcox.test in R-2.2.1 (stable). It wasn't there when I last taught nonparametrics in fall 2003. Line 86 of wilcox.test.R achieved.alpha<-2*psignrank(trunc(qu),n) It should be achieved.alpha<-2*psignrank(trunc(qu)-1,n) If you don't see why, decode the cookbook instructions p. 56 in Hollander and Wolfe (2nd ed.) or see

Hi Everyone, Following the previous discussion on optimizing *wilcox functions, Andreas Loeffler brought to my attention a few other bugs in `wilcox` family functions. It seems like these issues have been discussed online in the past few months, but I haven?t seen discussion on R-devel...unless I missed an email, it seems like discussion never made it to the mailing list. I haven?t seen any bug

Hi, I noticed this problem on my home desktop running FC4 and again on my laptop running FC5. Both have previously compiled and passed make check-all on 2.3.1 svn revisions from 10 days ago or so. On both these machines, make check-all is consistently failing (4 out of 4 attempts on the FC 4 desktop and 3 out of 3 on the FC 5 laptop) in the p-r-random-tests tests. This is with both default

hi, when performing a wilcox.test or a wilcox.exact i get results that looks like this: wilcox.exact(x, mu=.5) Exact Wilcoxon signed rank test data: x V = 207, p-value = 0.0006905 alternative hypothesis: true mu is not equal to 0.5 the way i understand the wilcox.test (or wilcox.exact) the V-value represents the summed up ranks of either the positive or negative differences,

On a recent FreeBSD 8.0-CURRENT (i386) building R (any version) breaks with the following messages: ---------------------------------------------------------------------- [...snip...] gcc -std=gnu99 -I. -I../../src/include -I../../src/include -I/usr/local/include -DHAVE_CONFIG_H -g -O2 -c wilcox.c -o wilcox.o gcc -std=gnu99 -I. -I../../src/include -I../../src/include -I/usr/local/include

how do I check the rank of a matrix ? say A= 1 0 0 0 1 0 then rank(A)=2 what is this function? thanks I did try help.search("rank"), but all the returned help information seem irrelevant to what I want. I would like to know how people search for help information like this. rank(base) Sample Ranks SignRank(stats) Distribution of the

hi, i am looking for a way to correct for ties in the wilcoxon signed rank test -> e.g. wilcox.test(x,mu=.5) one way i have heard of is to look up the p value in a table that has been produced by Buck (1975). obviously i need to know the T-value to do that -> how do i get the T-value from the wilcox.test() function. is there any other (already implemented) way to correct for ties in

Dear all, I have two samples that I need to compare. Running Shapiro Wilk normality test does not allow me to reject the normality assumption neither for the first sample (p-value = 0.8938) not for the second one (p-value = 0.07905). So the t.test seems to be applicable. However, the p-value for the second sample seems to be quite close to 0.05 threshold, so wouldn't it be better to use a

Hi, In the exactRankTest package, I've become aware that you can get anomalous p-values (i.e., above 1) from the wilcox.exact method, as in: > wilcox.exact(c(-0.6,0.8,-0.5)) Exact Wilcoxon signed rank test data: c(-0.6, 0.8, -0.5) V = 3, p-value = 1.25 alternative hypothesis: true mu is not equal to 0 This is disturbing. Has anyone encountered this before, and if so

Hi, When I execute a Wilcox u-test on two variables I receive a warning : 'cannot compute exact p-value with ties' - What are ties? What does this mean for my data? - Is that a problem for significance testing? - is there a way to overcome this problem? I have different threads in this forum but it hard to find what the exact meaning of this warning message is. -- View this message in

Full_Name: David Wooff Version: 1.7.0 OS: i686-pc-linux-gnu Submission from: (NULL) (129.234.4.10) wilcox.test exits with error message when confidence interval required, under some situations. I suspect this occurs when the data contain a zero and for some data lengths only: print(wilcox.test(c(2,1,4,3,6,-5,0),conf.int=T)) fails print(wilcox.test(c(2,1,4,3,6,-5,0,1),conf.int=T)) works

Dear R Core, pairwise.wilcox.test does not handle "paired = TRUE" correctly; e.g. set.seed(13) x <- rnorm(20) g <- c(rep(1, 10), rep(2, 10)) wilcox.test(x ~ g)$p.value # 0.075 pairwise.wilcox.test(x, g)$p.value # 0.075, o.k wilcox.test(x ~ g, paired = TRUE)$p.value # 0.105 pairwise.wilcox.test(x, g, paired = TRUE)$p.value # 0.075, wrong The line wilcox.test(xi, xj,

Dear Developers Team, I have two items: 1. wilcox.test with the paired=T option appears to delete zeros before ranking absolute differences. Would it be possible to add the feature of removing zeros after ranking, which is given in Lehmann's Nonparametrics as the preferred choice. See also Pratt (1959), JASA 54, 655-667. It is given in wilcoxsign_test of the coin package as an option

Your second issue seems like a more or less unavoidable floating-point computation issue. The paired test operates by computing differences between corresponding values of x and y. It's not impossible to try to detect "almost-ties" (by testing for differences less than, say, sqrt(.Machine$double.eps)), but it's delicate and somewhat subjective/problem-dependent. Example:

does anybody know why there are the two warnings in the example above? Regards Knut > day_4 [1] 540 1 1 1 1 1 1 300 720 480 > day_1 [1] 438 343 1 475 1 562 500 435 1045 890 > is.vector (day_1) [1] TRUE > is.vector (day_4) [1] TRUE > wilcox.test(day_4 ,day_1,paired=TRUE,alternative="two.sided",exact=TRUE,conf.int=TRUE) Wilcoxon

Does anyone know why wilcox.exact gives W-statistic 6 instead of 12 as indicated below. 12 is the rank sum of group 0 of x, which is the linear statistic computed by wilcox_test. y<-c(1,2,3,4,5) x<-c(1,1,0,0,0) (a) wilcox.exact wilcox.exact(y~x) Exact Wilcoxon rank sum test data: y by x W = 6, p-value = 0.2 alternative hypothesis: true mu is not equal to 0 (b) wilcox_test

Dear all, When we perform a Wilcoxon rank sum test (on two samples with different sizes) we get a test statistic. My question is, as the value of test statistic increases the difference between the distributions of the two samples also increase, right? Thanks in advance, João Fadista [[alternative HTML version deleted]]

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I have a stupid question on how to get the real p-values for wilcox.test and correlation. the minmun can be reached is 2.2E-16 using the R version 2.6.2. I do not think it is the R version causing this but other issues. Any help is highly appreciated. Charles -- View this message in context: http://www.nabble.com/minmun-p-value-for-wilcox.test-and-correlation-tp23637568p23637568.html Sent