Displaying 20 results from an estimated 7000 matches similar to: "rank of a matrix"
2012 Jan 10
4
2 sample wilcox.test != kruskal.test
Hello,
I think I am right in saying that a 2 sample wilcox.test is equal to a 2
sample kruskal.test and
a 2 sample t.test is equal to a 2 sample anova. This is also stated in the
?kruskal.test man page:
The Wilcoxon rank sum test (wilcox.test) as the special case for two
samples; lm together with anova for performing one-way location analysis
under normality assumptions; with Student's t
2012 Dec 15
3
kruskalmc, significant differences while median values are the same
Dear list!
I work with multiple Kruskal-Wallis test (kruskalmc, package pgirmess), which evaluates differences in medians among groups (5 groups). A result of a test is significant differences among some groups, while median values are the same for 4 groups (using tapply). Why?
p.s.: number of samples in groups vary from 50 to 4900.
Thanks to all, OV
.
2011 Nov 01
1
help with unequal variances
Hello,
I have some patient data for my masters thesis with three groups (n=16, 19 &
20)
I have completed compiling the results of 7 tests, for which one of these
tests the variances are unequal.
I wish to perform an ANOVA between the three groups but for the one test
with unequal variance (<0.001 by both bartlett and levene's test) I am not
sure what to do.
I thought i would run
2009 Oct 14
3
post-hoc test with kruskal.test()
Dear R users,
I would like to know if there is a way in R to execute a post-hoc test
(factor levels comparison, like Tukey for ANOVA) of a non-parametric
analysis of variance with kruskal.test() function. I am comparing three
different groups. The preliminary analysis using the kruskal-wallis-test
show significance, but I still don''t know the relationship and the
significance level
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:
2010 Aug 17
3
Wilcoxon test and grouping factor with multiple levels
Dear R users,
I have a dataset with two variables: $esan - a grouping factor with 8
levels and $reus. I'd like to do wilcox.test on this dataset as
sugested Weiwei here:
https://stat.ethz.ch/pipermail/r-help/2007-July/136627.html. I tried
to adapt his recommendation but no succes. Can anyone help me?
Regards,
Iurie Malai, Senior Lecturer
Department of Psychology
Faculty of Psychology and
2009 Jan 08
1
Letter-based representation of pairwise comparisons
Hi!
I have been working several years with R but it's my first public question.
I hope I'll be clear :) .
This question is related to obtaining letter-based representation of
non-parametric pairwise comparisons.
I have a dataframe with this structure (but with quite more rows and cols):
A B C factor
1 2 2 one
2 1 2 one
2 2 3 two
2 3 2 two
1 4 2 three
9 8 1 three
I have no normality,
2011 May 24
3
test de Friedman , con comparación planificada simple (la primera contra el resto...).
Hola.
Hay alguna función que haga un Friedman test (digamos 4 tratamientos o
tiempos relacionados/dependientes) y que después haga una comparación
de un tratamiento contra el resto, digamos el primero, como un
contratase simple, o un Dunnett?
o simplemente ¿como hago un Dunnett para unos tratamientos relacionados?
--
Antonio M
[[alternative HTML version deleted]]
2011 Apr 28
3
Simple General Statistics and R question (with 3 line example) - get z value from pairwise.wilcox.test
Hi there,
I am trying to do multiple pairwise Wilcoxon signed rank tests in a
manner similar to:
a <- c(runif(1000, min=1,max=50), rnorm(1000, 50), rnorm(1000, 49.9,
0.5), rgeom(1000, 0.5))
b <- c(rep("group_a", 1000), rep("group_b", 1000), rep("group_c",
1000), rep("group_d", 1000))
pairwise.wilcox.test(a, b, alternative="two.sided",
2012 Jul 24
2
Wilcoxon V = 0
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=a$x,y=b$x,paired=TRUE)
The output looks like this:
Wilcoxon
2011 Apr 12
2
The three routines in R that calculate the wilcoxon signed-rank test give different p-values.......which is correct?
I have a question concerning the Wilcoxon signed-rank test, and
specifically, which R subroutine I should use for my particular dataset.
There are three different commands in R (that I'm aware of) that calculate
the Wilcoxon signed-rank test; wilcox.test, wilcox.exact, and
wilcoxsign_test. When I run the three commands on the same dataset, I get
different p-values. I'm hoping that
2010 Feb 24
1
extracting results from wilcox_test (package::coin)
Recently, I ran a series of Kruskal-Wallace tests [kruskal.test()] using by()
to group by site Output is a list:
>Herb.KW
Herb.df$ID: 10-1
Kruskal-Wallis rank sum test
data: Indicator_Rating by Year
Kruskal-Wallis chi-squared = 15.24, df = 7, p-value = 0.03302
-----------------------------------------------------------------------------------------------------
Herb.df$ID: 18-1
2012 Jan 12
2
kruskal wallis post hoc?
Dear all,
I run a kruskal wallis test and found significant results. Then, I conducted all pairwise comparisons and found no significant results. Could anyone please give me a hint as to why this happens or redirect me towards a specific web page where I can find more info? (I used alpha=5% and made no bonferroni or other correction for the pairwise comparisons)
Thank you
Dr. Iasonas
2005 May 16
1
Mann-Whitney & Wilcoxon Rank Sum
Hello,
I am hoping someone could shed some light into the Wilcoxon Rank Sum Test
for me? In looking through Stats references, the Mann-Whitney U-test and
the Wilcoxon Rank Sum Test are statistically equivalent. When using the
following dataset:
m <- c(2.0863,2.1340,2.1008,1.9565,2.0413,NA,NA)
f <- c(1.8938,1.9709,1.8613,2.0836,1.9485,2.0630,1.9143)
and the wilcox.test command as
2010 Jun 23
3
Wilcoxon signed rank test and its requirements
Hi all,
I have a distribution, and take a sample of it. Then I compare that sample with the mean of the population like here in "Wilcoxon signed rank test with continuity correction":
> wilcox.test(Sample,mu=mean(All), alt="two.sided")
Wilcoxon signed rank test with continuity correction
data: AlphaNoteOnsetDists
V = 63855, p-value = 0.0002093
alternative hypothesis:
2009 Sep 07
1
Equivalence of Mann-Whitney test and Kruskal-Wallis test with k=2
Hi all,
The Kruskal-Wallis test is a generalization of the two-sample Mann-Whitney
test to *k* samples. That being the case, the Kruskal-Wallis test with *k*=2
should give an identical p-value to the Mann-Whitney test, should it not?
x1<-c(1:5)
x2<-c(6,8,9,11)
a<-wilcox.test(x1,x2,paired=FALSE)
b<-kruskal.test(list(x1,x2),paired=FALSE)
a$p.value
[1] 0.01587302
b$p.value
[1]
2006 Apr 27
1
Looking for an unequal variances equivalent of the Kruskal Wallis nonparametric one way ANOVA
Well fellow R users, I throw myself on your mercy. Help me, the unworthy,
satisfy my employer, the ungrateful. My feeble ramblings follow...
I've searched R-Help, the R Website and done a GOOGLE without success for a
one way ANOVA procedure to analyse data that are both non-normal in nature
and which exhibit unequal variances and unequal sample sizes across the 4
treatment levels. My
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
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
2005 Aug 28
2
stratified Wilcoxon available?
Dear All,
is there a stratified version of the Wilcoxon test (also known as van
Elteren test) available in R?
I could find it in the survdiff function of the survival package for
censored data. I think, it should be possible to use this function creating
a dummy censoring indicator and setting it to not censored, but may be
there is a better way to perform the test.
Thanks,
Heinz T??chler