Displaying 20 results from an estimated 10000 matches similar to: "wilcox.test; data type conversion?"
2011 May 05
4
Using functions/loops for repetitive commands
I still need to do some repetitive statistical analysis on some outcomes
from a dataset.
Take the following as an example;
id sex hiv age famsize bmi resprate
1 M Pos 23 2 16 15
2 F Neg 24 5 18 14
3 F Pos 56 14 23 24
4 F Pos 67 3 33 31
5 M Neg 34 2 21 23
I want to know if there are statistically detectable differences in all of
the continuous variables in
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))
>
2009 Aug 12
1
what is the difference between the two logistic models?
Hi All,
I have data with 400 individuals and the following information
Grade: pass or fail coded as 1 for pass and 0 for fail
Sex: male or female ( coded as 1 for male and 2 for female )
Age
Teaching.method : can be 1,2,3
I want to fit a logistic regression where the outcome if (1=pass or 0 for
fail) and the rest of the variables are the regressors.
My question is that I am not sure
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)
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
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",
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
2008 Nov 12
2
pairwise.wilcox.test
Un texte encapsul? et encod? dans un jeu de caract?res inconnu a ?t? nettoy?...
Nom : non disponible
URL : <https://stat.ethz.ch/pipermail/r-help/attachments/20081112/618073fe/attachment.pl>
2006 May 12
1
wilcox.exact function (PR#8856)
Full_Name: Patrick Hodgson
Version: 2.0
OS: solaris 2.9
Submission from: (NULL) (65.94.128.161)
The value reported for the parameter W in the function wilcox.exact appears to
be incorrect. I have checked the reference in the help file for this function
(Myles & Hollander 1973, as well as 2nd ed. 1999 by same authors) and it is
clear that W is the sum of the ranks of the data set with the
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:
2001 Dec 13
2
Problem to interpret wilcox.test
I've got two set of data :
22.45 21.56 20.48 19.59 21.52 = A
and
22.15 21.98 20.42 20.58 19.61 = B
I perform a wilcox.test on this two set
wilcox.test(A, B) and I'd this answer:
Wilcoxon rank sum test
data: A and B
W = 12, p-value = 1
alternative hypothesis: true mu is not equal to 0
Should I interpret that there is no difference between the two sets ?
--
Cordialement
2009 Aug 04
3
Logistic Regression
Hi,
Trying to setup a logistic regression model. (Something new to me. I
usually use SVM.)
The person explaining the concept explained to me that I can include a
"group" variable so that the probabilities predicted by the model will
be "per group"
Does this make sense to anyone? If so, how would I implement this?
Using the glm or lrm function?
Thanks!
-N
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.
2006 Jan 12
1
wilcox.test warnig message p-value where are the zeros in the data?
does anybody know why there are the two warnings in the example above?
Regards Knut
> day_4
[1] 540 1 1 1 1 1 1 300 720 480
> day_1
[1] 438 343 1 475 1 562 500 435 1045 890
> is.vector (day_1)
[1] TRUE
> is.vector (day_4)
[1] TRUE
> wilcox.test(day_4
,day_1,paired=TRUE,alternative="two.sided",exact=TRUE,conf.int=TRUE)
Wilcoxon
2003 Jan 14
1
ctest package: wilcox.test() produces integer overflow (PR#2453)
This was filed as a bug report on the Debian r-base package. It is
more properly a bug report on the ctest package in R.
The default method for wilcox.test manipulates x and y without
checking the class or data.class of these objects. Possible solutions
are
- create wilcox.test.factor (if appropriate)
- check the class and/or data.class of x and y in wilcox.test.default
and produce error
2007 Oct 17
2
wilcox.test test statistic
Dear all,
When we perform a Wilcoxon rank sum test (on two samples with different sizes) we get a test statistic. My question is, as the value of test statistic increases the difference between the distributions of the two samples also increase, right?
Thanks in advance,
João Fadista
[[alternative HTML version deleted]]
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,
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
2005 Aug 17
1
trouble with wilcox.test
I'm having trouble with the wilcox.test command in R. To demonstrate the anomalous behavior of wilcox.test, consider
> wilcox.test(c(1.5,5.5), c(1:10000), exact = F)$p.value
[1] 0.01438390
> wilcox.test(c(1.5,5.5), c(1:10000), exact = T)$p.value
[1] 6.39808e-07 (this calculation takes noticeably longer).
> wilcox.test(c(1.5,5.5), c(1:20000), exact = T)$p.value
(R closes/crashes)
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