Displaying 20 results from an estimated 3000 matches similar to: "mann-whitney test with more groups"
2009 Aug 26
3
mann whitney u
Dear Sir,
I am comparing two samples using wilcox.test in R. Literature appears to describe mann whitney u test as the most appropriate test to use on my data.
is the wilcox.test function equivalent to mann-whitney u? Is there a way to gain the U-value as apposed to the W-value in R?
Thank you
2009 Jul 11
2
mann-whitney U-test - U-value
Hi,
I know that I can perform a Mann-Whitney U test with wilcox.test(x,y)
But instead of an U-value I get a W-Value.
Is it possible to change this?
2005 May 16
1
Mann-Whitney & Wilcoxon Rank Sum
Hello,
I am hoping someone could shed some light into the Wilcoxon Rank Sum Test
for me? In looking through Stats references, the Mann-Whitney U-test and
the Wilcoxon Rank Sum Test are statistically equivalent. When using the
following dataset:
m <- c(2.0863,2.1340,2.1008,1.9565,2.0413,NA,NA)
f <- c(1.8938,1.9709,1.8613,2.0836,1.9485,2.0630,1.9143)
and the wilcox.test command as
2011 Oct 06
1
Wilcox Test / Mann Whitney U Test
Hello List,
I'm trying to prepare some lecture notes on non parametric methods,
and I can't manually reproduce the results of the wilcox.test function
for ordinal data.
The data I'm using are from David Howell's website, available here
http://www.uvm.edu/~dhowell/StatPages/More_Stuff/OrdinalChisq/OrdinalChiSq.html
If I run the wilcox.test function on the data I get a p-value of
2009 Sep 07
1
Equivalence of Mann-Whitney test and Kruskal-Wallis test with k=2
Hi all,
The Kruskal-Wallis test is a generalization of the two-sample Mann-Whitney
test to *k* samples. That being the case, the Kruskal-Wallis test with *k*=2
should give an identical p-value to the Mann-Whitney test, should it not?
x1<-c(1:5)
x2<-c(6,8,9,11)
a<-wilcox.test(x1,x2,paired=FALSE)
b<-kruskal.test(list(x1,x2),paired=FALSE)
a$p.value
[1] 0.01587302
b$p.value
[1]
2007 Aug 14
4
Mann-Whitney U
Hi,
Could someone please tell me how to perform a Mann-Whitney U test on a
dataset with 2 groups where one group has more data values than another?
I have split up my 2 groups into 2 columns in my .txt file i'm using with
R. Here is the code i have so far...
group1 <- c(LeafArea2)
group2 <- c(LeafArea1)
wilcox.test(group1, group2)
This code works for datasets with the same number
2003 Feb 15
2
How to code a bootstrap version of the Wilcoxon-Mann-Whitney test (and variants)?
Hello,
can someone please help me with coding a function for a bootstrap WMW test (package boot, R under Windows, version 1.6.2)?
2012 May 29
2
Wilcoxon-Mann-Whitney U value: outcomes from different stat packages
Given this example
#start code
a<-c(0,70,50,100,70,650,1300,6900,1780,4930,1120,700,190,940,
760,100,300,36270,5610,249680,1760,4040,164890,17230,75140,1870,22380,5890,2430)
b<-c(0,0,10,30,50,440,1000,140,70,90,60,60,20,90,180,30,90,
3220,490,20790,290,740,5350,940,3910,0,640,850,260)
wilcox.test(a, b, paired=FALSE)
#sum of rank for first sample
sum.rank.a <-
2012 Jul 06
1
Mann-Whitney by group
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
2013 Oct 02
5
Interpreting the result of a Wilcoxon (Mann-Whitney U) test
Hello everyone,
I'm having some trouble interpreting the results of a Wilcoxon
(Mann-Whitney U) test. Hope you can help.
This is the R script that I am running:
a <- c(1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 1, 5, 1, 1, 1, 3, 1, 1,
1, 1, 1, 1, 3, 1, 1)
b <- c(1, 2, 1, 1, 2, 3, 2, 2, 1, 2, 1, 1, 1, 2)
wilcox.test(a, b, alternative="t", mu=0, exact=FALSE, paired=FALSE) #1st
2007 Aug 15
0
Mann-Whitney U test discrepancies
Hi,
I do want to use the Mann-Whitney test which ranks my data and then
uses
those ranks rather than the actual data.
Here is the R code i am using:
group1<-
c(1.34,1.47,1.48,1.49,1.62,1.67,1.7,1.7,1.7,1.73,1.81,1.84,1.9,1.96,2,
2,2.19,2.29,2.29,2.41,2.41,2.46,2.5,2.6,2.8,2.8,3.07,3.3)
> group2<-
2009 Feb 14
1
Mann Whitney test
Hi,
I have a statistical question.
To apply the Mann Whitney test to compare a pair of vectors, they must to
have the same length ?
Thanks,
Rodrigo
[[alternative HTML version deleted]]
2003 Aug 26
1
Mann-Whitney U Table
Does anyone have a piece of code or know how I can use R to generate a table
of
critical values for the Mann-Whitney (aka Wilcoxon Rank Sum) test.
Ideally, I'd like a table that contains the critical values for any two
samples of size 3 through 30. I could use Monte Carlo simulation or the
normal approximation when n1 and n2 are greater than, 10, but I figured
someone may know how to
2005 Dec 20
1
Wilcoxon Mann-Whitney Rank Sum Test in R
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
2005 Feb 24
0
How to code a bootstrap version of the Wilcoxon-Mann-Whitney test?
Dear Stefan
I need to apply a Mann Whitney test to my data, by applying a bootstrap, in
R.
Loonkig for an answer in internet I found your question to the R mailing
list but I have not found the answer to your question.
Please, could you help me?
thank you very much in advance.
Best regards
Luciana
2011 Sep 21
0
Resumen de R-help-es, Vol 31, Envío 12 Mann-Whitney U Test
>Hola colegas, no encuentro como hacer el Mann-Whitney U Test en R.
>
> Alguna solución?????
>
> Un abrazo a todos.
>
> Leonardo
>
Hola Leonardo:
La prueba de Mann-Whitney también se conoce como la prueba de suma de rangos de wilcoxon y puede calcularse mediante la función wilcox.test
Un saludo,
Nicolás Benítez Parejo
Técnico de Evaluación e Investigación
Agencia
2016 Mar 28
7
Mann-Whitney con datos temporales
Hola a tod en s,
queremos hacer una comparación entre dos lugares muy alejados entre sí
en relación a la temperatura de cada sitio usando medias horarias de
un período determinado. Sólo hay medidas de un sensor en cada sitio y
queremos saber si las diferencias son significativas o no entre
sitios/curvas. Hemos usado un test de Mann?Whitney U con la función
wilcox.test (paired=F) ya que los
2009 Apr 14
1
mean fold change issues and p values
I am new to R and have two scripts written slightly different but should to relatively the same thing but my lack of experience with the program I can not figure out the what I need to do to correct it. The first script gives me a consistent mean fold change values with every run but can generate negative p values for some. For the second version of the script, the fold changes seem to be very
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
2010 Aug 20
2
U value from wilcox.test
Dear all,
I want to compare the efficiency of 2 methods in extracting proteins from
algal samples. I collected 6 independant algal samples and I extracted 3 by
the method 1 and 3 others by the method 2.
So I have 2 groups of 3 samples, that are not paired. I would like to know
if the results obtained by these 2 methods are significantly different, I
hope method 2 to be more efficient than method