Displaying 20 results from an estimated 5000 matches similar to: "gamma distribution"
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
2005 Jan 22
1
Wilcoxon test for mixed design (between-within subjects)
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 single block and replicated
observations. Is
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
2003 Jun 11
1
qwilcox
The function 'wilcox.test' in R and S gives (almost) identical results (see
below). 'qwilcox' however, does not:
> qwilcox(p,5,5)
p: 0.025 0.975
--------------------
R> 3 22
S> 18 37
I originally wanted to ask a questions, but then I found the answer. Given
the confusion I run into, I wonder if this experience is worth reporting.
The
2005 Nov 14
1
effect sizes for Wilcoxon tests
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
2005 May 04
4
rank of a matrix
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
2009 Oct 23
4
How to apply the Wilcoxon test to a hole table at once?
Hi,
I have a data set:
> Dataset
X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17
1 user1 m 22 19 28 24 12 18 9 7 4 5 4 7 5 7 9
2 user2 f 25 19 23 18 18 15 6 8 6 6 7 10 7 7 7
3 user3 f 28 21 24 18 15 12 10 6 7 9 5 10 5 9 5
4 user4 f 26 19 26 21 12 18 6 6 5 1 3 8 6 5 6
5 user5 m 21 22 26 18 9 6 4 6 1
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))
>
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
2003 Oct 07
3
FW: Optimising code
>> I have a function that applies a wilcoxon test to 12 sets of about a quarter of a million pairs
> ... and let me guess: everything is significiant to an almost arbitrary
> value of \alpha?
:-) For each of quarter of a million sets, I do a wilcoxon between two pairs each containing twenty numbers...
I do this 12 times...
> > (and takes about 3 hours). I've replaced the
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.
2010 Jun 23
3
Wilcoxon signed rank test and its requirements
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:
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)
2003 Dec 01
2
wilcoxon-pratt signed rank test in R - drug-effiacy
Hi.
I'm going to introduce the R-package for a group of medical doctors later
this week 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
2013 May 30
1
wilcox_test function in coin package
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
2000 Dec 18
2
Help: StatXact
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,
2010 Nov 24
3
Límites de confianza de la mediana en distribuciones simétricas
Por si alguno pudiera ayudarme.
Al realizar el t.test para una muestra, junto con el valor de t y el
p-valor, la función proporciona la estimación de la media y su INTERVALO
DE CONFIANZA.
Desde el punto de vista de la estadística de rangos esto se puede hacer
mediante:
> iris$MEDIANA <- with(iris, 2.95)
> median(iris$Sepal.Width - iris$MEDIANA, na.rm=TRUE) # median difference
[1]
2004 May 12
3
mannwitney
Hi,
I would like to do a MannWitney test.
Can anyone help me with the propper command?
Thanks,
Margarida
2009 Mar 02
3
Help with Wilcoxon Test
Hi
I have 2 sets of data that I want to do a Wilcoxon test on. They are of the same dimension. One has 4 zero values and the other has 5.
> dim(SampA)
[1] 1 10
> dim(SampV)
[1] 1 10
I get the folowing error
Error in wilcox.test.default(SampA, SampV, na.rm = TRUE, paired = FALSE, :
'x' must be numeric
I am using the function
wilcox.test(SampA, SampV, na.rm=TRUE,
2010 Oct 29
2
wilcox.test; data type conversion?
I'm working on a quick tutorial for my students, and was planning on
using Mann-Whitney U as one of the tests.
I have the following (fake) data
grade <- c("MVG", "VG", "VG", "G", "MVG", "G", "VG", "G", "VG")
sex <- c( "male", "male", "female", "male",