similar to: Exact wilcoxon may differ in R and SPSS/StatXact (due to round off in the latter pair)

Hi, I became a little bit confused when working with the Wilcoxon test in R. As far as I understood, there are mainly two versions: 1) wilcox.test{stats}, which is the default and an approximation, especially, when ties are involved 2) wilcox_test{coin}, which does calculate the distribution _exactly_ even, with ties. I have the following scenario: #---BeginCode--- # big example size = 60

Help needed! Has anyone access to StatXact? I just hacked exact two-sided p-values for rank tests (for package exactDistr, which will move to CRAN/contrib as exactRankTests soon ;-) and would like to compare the results of my implementation to that of StatXact. Could someone please calculate the exact one-sided (both greater and less) and two-sided p-values? # Data from the StatXact-4 manual,

Hi, Two functions wilcox.exact and wilcox_test give slightly different confidence intervals of the difference of the medians: for example y<-c(0,0,1.081,0.594,0,0.769,0,0.009,0,0,0.798,0.405,0.498,0.946,1.35,1.149,0.528) x<-c(rep(1,10),rep(2,7)) aa<-wilcox.exact(y~x,conf.int=TRUE) bb<-wilcox_test(y~factor(x),distribution="exact",conf.int=TRUE) aa bb Does anyone know

Another example: Jerry Friedman's MART is available in R from Salford for the same price as the stand-alone TreeNet, even though they don't advertise it on their web site. Andy > -----Original Message----- > From: rossini at blindglobe.net [mailto:rossini at blindglobe.net] > Sent: Sunday, August 17, 2003 9:50 PM > To: rhelp > Cc: pralay at cytel.com > Subject: [R]

At JSM, I spent a bit of time with old friends at the Cytel booth (makers of StatXact/LogXact). They were wondering whether it was both feasible and of interest to create a package of the StatXact compute engine for R (to be commercially licensed, not for free!), similar to what they've done for SAS. As far as I know, it's feasible, (this is not the first commercial external package,

An earlier post had posed the question: "Does anybody know what is relation between 'T' value calculated by 'wilcox_test' function (coin package) and more common 'W' value?" I found the question interesting and ran the commands in R and SPSS. The W reported by R did not seem to correspond to either Mann-Whitney U, Wilcoxon W or the Z which I have more

Hi, I am running the following example which can be found on page 12 of the pdf file of COIN package wt<-wilcox_test(pd~age,data=water_transfer,distribution="exact", conf.int=TRUE) "wt" actually contains the estimate of difference in location and the confidence interval of it. I am just wondering how can I extract these values? From the examples, I understand that the

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 R-forumites, I want to apply a Wilcoxon test on subsets of the data frame mydata, splitted using the myindice variable. When I send : wilcoxtest <- by(mydata, mydata$myindice, function(x) {wilcox_test(x$value~x$fact)}) I get : Error in eval(expr, envir, enclos) : object "x" not found whereas wilcoxtest <- by(mydata, mydata$myindice, function(x)

I need to perform the Exact Wilcoxon Mann-Whitney on a subset of my database. Assuming that IPPO is my data frame and IPPOBIS is the subset my variable still have 3 different levels and the function wilcox_test (package "coin") does not accept it. I do not know how to overcome this problem. ippo <- c(rep("A",10),rep("B",10),rep("C",10)) ippo2 <-

Hello, I use t.test for normal distributed and wilcox.test for non-normal distributed samples. It is easy to write a function for t.test that calculates the effect size, because all parts of the formula are available from the t.test result: r = sqrt(t*t / (t*t + df)) However, for Wilcoxon tests, the formula for effect sizes is: r = Z / sqrt(N) I wonder how I can calculate the Z-score in R for

Dear R, I'm looking for exact p-values for Spearman's rank correlation in the presence of ties. This is available in StatXact and SPSS, but I haven't yet found it in R. Has anyone implemented this? -- Paul H Artes Assist Prof, Ophth Vis Sci Dalhousie University, QEII Eye Care Centre Halifax, NS, CANADA

Dear All, I have two simple data samples (no groups or factors, etc.) and would just like to compute the two-sample Wilcoxon Rank Sum test using the wilcox_test function contained in the coin package, which is reportedly better than the regular wilcox.test function because it performs some adjustment for ties. Would anyone know how to craft a script to perform this task? Much appreciated. Janh

Probably, it's an obvious info, but I have not found anything in R FAQ concerning this feature/bug. The results of ks.test and wilcoxon.test (in the Mann-Whitney version, paired = 'FALSE') don't coincide with the results from the other statistical packages, e.g. Statistica, Medcalc, and (as for MW test) from the numerous online MW tests. E.g. Statistica p-value=0.0435353 Medcalc

Dear List, after updating the exactRanksumTests package I receive a warning that the package is not developed any further and that one should consider the coin package. I don't find the signed rank test in the coin package, only the Wilcoxon Mann Whitney U-Test. I only found a signed rank test in the stats package (wilcox.test) which is able to calculate the exact pvalues but unfortunately

Hello, I'm having some issues grouping cases for some Mann-Whitney U tests I'm attempting to run. I'm willing to use wilcox.test if it'll work; I've also tried wilcox_test() from the "coin" package. Here's the deal: for each column (A through H), I would like to run the two-sample independent test, comparing Group 5 (CD8.14 through CD8.17) to Group 6 (CD8.18

De la manera que me aconsejas no funciona y da este mansaje Warning message: In wilcox.test.default(x = c(19L, 18L, 17L, 16L, 18L, 19L, 18L, : cannot compute exact p-value with ties como aconsejaste tmp <- read.table("estudiantes1.csv", header=TRUE, sep=",", dec=".", na.strings = "NA") wt <- wilcox.test(IMC ~ a_HTA, data=tmp, paired = FALSE,

Hi! I need to run a wilcoxon (Mann-whitly, in fact) test with bonferroni correction, as I am running 10 consecutive wilcoxon test not independent, and I know that bonferroni will partially correct for this problem, but I have no idea how to do it with R, I have been looking in the archive but couldn't understand how to do it. The format I am using at the moment is r4_o <- [1]

Hello there, I would like to do a Wilcoxon matched pairs signed rank sum test in R and tried the function wilcoxon.test. Is it in the "base" library? If not, please let me know which library it is in. Thank you in advance for your help Lisa Wang Biostatistician Princess Margaret Hospital Toronto, Ca

Hi, R allows me to run a one sample Wilcoxon test like this: wilcox.test(c(1,3.5,2.1,4,1.5,5), mu=2, exact=TRUE) The function 'wilcoxsign_test' from the package 'coin' should (I suppose) be able to calculate exact p values even if there are ties in the ranks. However, I couldn't find information on how to run a one sample test using 'wilcoxsign_test' like in the