Displaying 20 results from an estimated 3000 matches similar to: "stratified Wilcoxon's rank sum test with the locally best weights"
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
2011 Apr 13
2
Wilcoxon rank sum in unbalanced design
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
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2007 Jun 28
1
Wilcoxon Rank Sum Test.
Dear,
I'm using R software to evaluate Wilcoxon Rank Sum Test and I' getting one
Warning message as this:
> C1dea_com
[1] 1.000 0.345 0.200 0.208 0.508 0.480 0.545 0.563 0.451 0.683 0.380 0.913
1.000 0.506
> C1dea_sem
[1] 1.000 0.665 0.284 0.394 0.509 0.721 0.545 0.898 0.744 0.683 0.382 0.913
1.000 0.970
> wilcox.test(C1dea_sem,C1dea_com, paired = TRUE, alternative =
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 Nov 24
2
Wilcoxon Rank Sum in R with a multiple testing correction
Hi there,
I'm a total newbie to R. I'd like to use a Wilcoxon Rank Sum test to compare
two populations of values. Further, I'd like to do this simultaneously for
114 sets of values. The two populations are C and N. The different sets of
values have arbitrary names (I'll call them a, b, c etc). The set-up is as
follows:
a b c d ....
C 2
C 3
C 5
C 9
C 4
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
2006 Sep 11
2
Wilcoxon Rank-Sum Test with Bonferroni's correction
Dear all,
I am trying to run Wilcoxon Rank-Sum Test with Bonferroni's
correction. I have two lists: l0, l1:
mapply(function(x,y)wilcox.test(x,y)$p.value, l0, l1)
How do I run Bonferroni's correction on mapply? Any help is much apperciated.
Thanks,
-Raj
2002 Mar 20
1
Wilcoxon Rank Sum Test
How does R compute the p-value in the Wilcoxon Rank Sum Test?
If I have the test statistics, can I get the p-value using the function
pwilcox?
Thanks
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2010 Sep 27
2
Sample size estimation for non-inferiority log-rank and Wilcoxon rank-sum tests
Hello Everyone,
I'm trying to conduct a couple of power analyses and was hoping someone might be able to help. I want to estimate the sample size that would be necessary to adequately power a couple of non-inferiority tests. The first would be a log-rank test and the second would be a Wilcoxon rank-sum test. I want to be able to determine the sample size that would be necessary to test for a
2004 Jun 08
0
bootstrap: stratified resampling
Dear All,
I was writing a small wrapper to bootstrap a classification algorithm, but if
we generate the indices in the "usual way" as:
bootindex <- sample(index, N, replace = TRUE)
there is a non-zero probability that all the samples belong to only
one class, thus leading to problems in the fitting (or that some classes will
end up with only one sample, which will be a problem
2009 Mar 28
1
stratified variables in a cox regression
>Hello,
I am hoping for assistance in regards to examining the contribution
of stratified variables in a cox regression. A previous post by Terry
Therneau noted that "That is the point of a strata; you are declaring
a variable to NOT be proportional hazards, and thus there is no
single "hazard ratio" that describes it". Given this purpose of
stratification, in the
2012 Jun 01
1
Stratified Sampling with randomForest Regression
Hi All,
I'm using R's randomForest package (and it's quite awesome!) but I'd
really like to do some stratified sampling with a regression problem.
However, it appears that the package was designed to only accommodate
stratified sampling for classification purposes (see
https://stat.ethz.ch/pipermail/r-help/2006-November/117477.html). As
Andy suggests in the link just
2011 Mar 10
1
ANOVA for stratified cox regression
This is a follow-up to a query that was posted regarding some problems that
emerge when running anova analyses for cox models, posted by Mathias Gondan:
Matthias Gondan wrote:
>* Dear List,*>**>* I have tried a stratified Cox Regression, it is working fine, except for*>* the "Anova"-Tests:*>**>* Here the commands (should work out of the box):*>**>*
2013 Apr 24
2
Regression on stratified count data
Hi all:
For stratified count data,how to perform regression analysis?
My data:
age case oc count
1 1 1 21
1 1 2 26
1 2 1 17
1 2 2 59
2 1 1 18
2 1 2 88
2 2 1 7
2 2 2 95
age:
1:<40y
2:>40y
case:
1:patient
2:health
oc:
1:use drug
2:not use drug
My purpose:
Anaysis whether case and
2008 Dec 11
1
How to generate a prediction equation for a stratified survival model that was fitted by cph() in Design package
Dear all,
I used cph() function from Frank harrell's Design package to create a
survival model, then used functions 'Function' and 'sascode' to generate
prediction equation based on the saved survival model. But it failed. I
included a stratified variable in the model. If I removed the
stratification, they were working well. Does that mean that function
'Function'
2013 Jan 10
1
SRS, Stratified, and Cluster sampling
Hi,
Has anyone done (or know of) any nice R activities that help introductory
students ( and teachers :) ) better understand the concepts of simple vs
stratified vs cluster sampling?
Any links?
David
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2008 Jan 15
1
Anova for stratified Cox regression
Dear List,
I have tried a stratified Cox Regression, it is working fine, except for
the "Anova"-Tests:
Here the commands (should work out of the box):
library(survival)
d = colon[colon$etype==2, ]
m = coxph(Surv(time, status) ~ strata(sex) + rx, data=d)
summary(m)
# Printout ok
anova(m, test='Chisq')
This is the output of the anova command:
> Analysis of Deviance Table
2011 May 13
0
routine for dependent correlation test with stratified random sample
Dear R-List,
I would like to have a large number of stratified random subsamples drawn from my dataframe and automatically test for correlation differences in every subsample.
Let this be my dataframe
df<-data.frame(group=c(rep(1,5),rep(2,5),rep(3,5)),a=c(3,4,5,6,3,4,5,4,5,4,1,2,1,2,1),b=c(1,2,3,4,5,3,4,3,4,5,6,5,6,2,3),c=c(2,2,3,3,5,1,1,6,6,5,6,1,1,2,1))
Then I would like to have n
2010 Apr 04
2
calculating an interaction statistic from stratified data
Dear R community,
I have data on beta&standard error (for the main effect of variable x),
stratified by sex for my dataset. I wish to calculate the sex-interaction
effect (as beta&se) from these two stratified datasets. Is there a package
to do this? If not, any advice how to do it manually?
Thank you very much and best regards, Georg.
************************
Georg Ehret, JHU,
2012 Oct 13
4
Problems with coxph and survfit in a stratified model with interactions
I?m trying to set up proportional hazard model that is stratified with
respect to covariate 1 and has an interaction between covariate 1 and
another variable, covariate 2. Both variables are categorical. In the
following, I try to illustrate the two problems that I?ve encountered, using
the lung dataset.
The first problem is the warning:
To me, it seems that there are too many dummies