Displaying 20 results from an estimated 4000 matches similar to: "wilcox.exact function (PR#8856)"
2005 Mar 21
1
anomalous result for wilcox.exact in exactRankTests
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
2006 Oct 05
1
The W statistic in wilcox.exact
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
2002 Oct 15
2
V-value in the wilcox.test resp. wilcox.exact
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,
2009 Oct 27
1
wilcox.exact() problem
Dear R friends,
here I write again about the wilcox.exact() problem. I want to compare two sets of categorical data, and in one case it says "negative length vectors not allowed", and in the other one I get the error "cannot allocate vector of length ...".
On http://rapidshare.com/files/298621893/wilcox.exact_trouble.Rdata.html you can download the data that cause the
2001 Oct 26
2
wilcox.test point estimates perverse (PR#1150)
The point estimates produced by wilcox.test are perverse (not wrong, just
brain damaged). The Hodges-Lehmann estimator that goes with the signed
rank test is the median of the Walsh averages. The Hodges-Lehmann estimator
that goes with the rank sum test is the median of the pairwise differences.
wilcox.test agrees except that it uses the following very peculiar definition
of "sample
2006 Aug 25
1
exact Wilcoxon signed rank test with ties and the "no longer under development" exactRanksumTests package
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
2010 Aug 09
1
Difference Between R: wilcox.test and STATA: signrank
This is my first post to the mailing list and I guess it's a pretty stupid
question but I can't figure it out. I hope this is the right forum for these
kind of questions.
Before I started using R I was using STATA to run a Wilcoxon signed-rank
test on two variables. See data below:
2009 Oct 16
2
"negative length vectors are not allowed" in wilcox.exact() and perm.test()
Dear R friends,
I want to compare two datasets and I get the message
Error in .Call("cpermdist2", ma = as.integer(m), mb = as.integer(col), :
negative length vectors are not allowed
after specifying the exact test. I'm using the exactRankTests package. Do you suggest me using the coin library, or is there anything "wrong" with my data?
Kind regards,
David
--
2003 Aug 06
1
wilcox.test, CI (PR#3666)
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
2002 Sep 26
1
T-Value, ties and the wilcox.test()
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
2019 Dec 07
5
Inconsistencies in wilcox.test
Hello,
Writing to share some things I've found about wilcox.test() that seem a
a bit inconsistent.
1. Inf values are not removed if paired=TRUE
# returns different results (Inf is removed):
wilcox.test(c(1,2,3,4), c(0,9,8,7))
wilcox.test(c(1,2,3,4), c(0,9,8,Inf))
# returns the same result (Inf is left as value with highest rank):
wilcox.test(c(1,2,3,4), c(0,9,8,7), paired=TRUE)
2006 Sep 29
1
Confidence interval in the Wilcoxon exact test
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
2006 Jan 29
0
Bug in wilcox.test
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
2011 Apr 12
2
The three routines in R that calculate the wilcoxon signed-rank test give different p-values.......which is correct?
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 dataset, I get
different p-values. I'm hoping that
2009 Nov 01
1
wilcox.test construction in r
Hi, I am very confused with constructing the wilcox.test in R.
I have two populations 'original' and 'test'.
I want to know if the 'test' is generally 'lower' than original.
I use alpha of 0.05.
So do I write the function as wilcox.test(original, test, alternative="l")?
or wlcox.test(original, test, alternative = "g")?
or wilcox.test(test,
2019 Dec 07
2
Inconsistencies in wilcox.test
Thank you for a fast response. Nice to see this mailing list being so
alive.
Regarding Inf issue: I agree with your assessment that Inf should not be
removed. The code gave me an impression that Inf values were
intentionally removed (since is.finite() was used everywhere, except for
paired case). I will try to adjust my patch according to your feedback.
One more thing: it seems like you
2019 Dec 12
2
Inconsistencies in wilcox.test
>>>>> Karolis Koncevi?ius
>>>>> on Mon, 9 Dec 2019 23:43:36 +0200 writes:
> So I tried adding Infinity support for all cases.
> And it is (as could be expected) more complicated than I thought.
"Of course !" Thank you, Karolis, in any case!
> It is easy to add Inf support for the test. The problems start with conf.int=TRUE.
2011 Jun 14
4
BIZARRE results from wilcox.test()
I get these BIZARRE results from wilcox.test()
When INCREASING the number of samples i get INCREASED p-values. When
increasing the number of samples further, the p-values goes down again. This
seems really bizarre!
Can anyone explain why this is so?!
Example:
> w <- wilcox.test(c(1:40),(c(1:40)+100))
> w$p.value
[1] 1.860340e-23
> w <- wilcox.test(c(1:50),(c(1:50)+100))
>
2010 Feb 08
1
Wilcoxon signed-ranks test using package coin ?
Given the following data, and hypothesized median M.0 I've found a
method to implement the Wilcoxon signed-rank test.
Data: (with one zero difference and tied ranks)
x <- c(136, 103, 91, 122, 96, 145, 140, 138, 126, 120, 99, 125,
91,142, 119, 137)
M.0 <- 119
> library(exactRankTests)
Package ?exactRankTests? is no longer under development.
Please consider using package ?coin?
2005 Mar 02
2
wilcox.test statistics
Hi,
Could anyone provide the formula of the statistics which the wilcox.test
used for the two-sample rank-sum test? I got some statistics of 0 values,
but it is impossible to have 0 "rank-sum". Does the function use the
Mann-Whitney U test statistics? Thanks.
Ting-Yuan Liu