search for: wilcoxon

I have a question concerning the Wilcoxon signed-rank test, and specifically, which R subroutine I should use for my particular dataset. There are three different commands in R (that I'm aware of) that calculate the Wilcoxon signed-rank test; wilcox.test, wilcox.exact, and wilcoxsign_test. When I run the three commands on the same...

...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 Wilcoxon Signed Rank Statistic Wilcoxon(stats) Distribution of the Wilcoxon Rank Sum Statistic friedman.test(stats) Friedman Rank Sum Test kruskal.test(stats) Kruskal-Wallis Rank Sum Test pairwise.wilcox.test(stats) Pairw...

...ons, but then I found the answer. Given the confusion I run into, I wonder if this experience is worth reporting. The S-Plus quantiles are almost correct (they are the limits of the region of acceptance, rather than the quantiles). The description in the R help file Distribution of the Wilcoxon Rank Sum Statistic suggests that R:qwilcox also gives quantiles for the rank sum (which the Wilcoxon rank sum test is based on). In fact, however, it gives quantiles for the u-statistic (which the Mann-Whitney test is based upon). While the tests are logically equivalent, the particular test st...

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 a Wilcoxon test. BTW, would it be correct to name "wilcox.test(..., paired=F)" a "Mann-Whitney test" in a report? If I understand the documentation (?wilcox.test) correct...

...1 3 8 6 5 6 5 user5 m 21 22 26 18 9 6 4 6 1 7 2 4 4 6 4 6 user6 m 24 8 25 12 18 12 7 8 4 1 4 6 7 5 6 ............................................................... 71 user71 m 18 4 10 6 3 6 9 5 10 8 4 5 6 5 5 I can apply the Wilcoxon test on each column one by one, but how to do this on the hole table at once? > wilcox.test(X3 ~ X2, alternative="two.sided", data=Dataset) Wilcoxon rank sum test with continuity correction data: X3 by X2 W = 439, p-value = 0.1291 alternative hypothesis: true location shift is no...

Hi all, I have a distribution, and take a sample of it. Then I compare that sample with the mean of the population like here in "Wilcoxon signed rank test with continuity correction": > wilcox.test(Sample,mu=mean(All), alt="two.sided") Wilcoxon signed rank test with continuity correction data: AlphaNoteOnsetDists V = 63855, p-value = 0.0002093 alternative hypothesis: true location is not equal to 0.4115136 &...

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! 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 ho...

...ek and is a little confused about there use of a test named "willcoxon-pratt" for testing if the clinical and biochemical markers has decreased significantly after the use of some drugs for a group of patients. Looking into the R-functions I would in R recommand using a matched-pairs Wilcoxon test with a formula like: wilcox.test(pre,post,alternative='greater',paired=T) Looking deeper into the writings of Pratt I found some 1964-stuff "Pratt JW. Remarks on zeros and ties in the Wilcoxon signed rank procedures. J.Americ.Statistical Assoc. 1959; 54: 655-67. " Do'...

Dear R-ers, I am currently running some Wilcoxon tests in R-64. How do I find the degrees of freedom in the output I am receiving? > wilcox.test(good$TRUE, good$x4a, paired=FALSE) Wilcoxon rank sum test with continuity correction data: good$TRUE and good$x4a W = 2455, p-value < 2.2e-16 alternative hypothesis: true location shift is...

Hi everyone! I need to perform a Wilcoxon rank sum test, but I have some ties and the groups have different size also. When I deal with ties I use the wilcox.exact function, how can I solve the different size problem using this function? thanks net -- View this message in context: http://r.789695.n4.nabble.com/Wilcoxon-rank-sum-in-unba...

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...

Dear R-users, I?m trying to perform a non-parametric statistical pairwise comparison of two samples "x" and "y" using the Wilcoxon test in R, but each of the pairs have a weight associated. An example of my data is the following one: set.seed(9) x <- sample(x = c(1:100), size = 20, replace = TRUE) y <- sample(x = c(1:100), size = 20, replace = TRUE) weight <- runif(n = 20) data <- data.frame(x = x, y = y, weight...

Dear all, I am using the ROCR library to compute the AUC and also the Hmisc library to compute the C-index of a predictor and a group variable. The results of AUC and C-index are similar and give a value of about 0.57. The Wilcoxon p-value is <0.001! Why the AUC is showing small value and the p-value is high significant? The AUC is based on Wilcoxon calculation? Many thanks, Lina [[alternative HTML version deleted]]

Hallo, is there any extension of the pairwise Wilcoxon test to a dependent samples layout with replicates (or, in other terms, a one-way layout with blocking and replicates)? The Wilcoxon method with matched pairs works for the case of dependent samples with one observation per block, while the Mann-Whitney test works for independent samples, thus one...

o <- (structure(list(sand.silt = structure(list(statistic = structure(185, .Names = "W"), parameter = NULL, p.value = 0.0478835773838087, null.value = structure(0, .Names = "location shift"), alternative = "two.sided", method = "Wilcoxon rank sum test with continuity correction", data.name = ".column by site"), .Names = c("statistic", "parameter", "p.value", "null.value", "alternative", "method", "data.name" ), class = "htest"), grave...

I am sure I am opening myself up to looking stupid, but I have two samples with medians of 613.5 and 189 (difference in location of 424 compared to the difference suggested from the wilcoxon of 291.5) > wilcox.test(pipwtCount,pipwdCount, conf.int=TRUE, na.rm=TRUE) Wilcoxon rank sum test data: pipwtCount and pipwdCount W = 822, p-value = 0.01227 alternative hypothesis: true location shift is not equal to 0 95 percent confidence interval: 58 639 sample estimates: difference...

Hello All, I am writing to ask your opinion on how to interpret this case. I have two vectors "a" and "b" that I am trying to compare. The wilcoxon test is giving me a pvalue of 5.139217e-303 of a over b with the alternative "greater". Now if I make a summary on each of them I have the following > summary(a) Min. 1st Qu. Median Mean 3rd Qu. Max. 0.0000000 0.0001411 0.0002381 0.0002671 0.0003623 0.0012910 &...

Dear everyone, I am trying to do a Wilcoxon one-sided test on my gene expression data. These are the data i have in R: data.matrix (matrix, numeric) containing all gene expression data (42 rows=genes, 42 columns=tumors), no column header or row names data.cl (vector, numeric) consisting of 42 0's and 1's to indicate class 0 or class...

I am running a pairwise wilcoxon signed rank test, and I am not sure how to interpret the result. I would like to see if there is a difference between the values in conditions a and b. It doesn't seem possible to have a V = 0, but a significant p value. Am I doing something wrong? The command I used is this: wilcox.test(x=...