Displaying 20 results from an estimated 3000 matches similar to: "wilcox_test function in coin package"
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
2017 Oct 14
3
Bootstrapped Regression
Greetings!
We are trying to obtain confidence and prediction intervals for a predicted
Y value from bootstrapped linear regression using the boot function. Does
anyone know how to code it? Greatly appreciated.
Janh
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2017 Oct 15
2
Bootstrapped Regression
Hello Rui,
Thanks for your helpful suggestions. Just for illustration, let's use the
well known Duncan dataset of prestige vs education + income that is
contained in the "car" package. Suppose I wish to use boot function to
bootstrap a linear regression of prestige ~ education + income and use the
following script:
duncan.function <- function(data, indices) {data =
2008 Jan 26
1
How to apply the wilcox_test function to subsets ?
Dear R-forumites,
I want to apply a Wilcoxon test on subsets of the data frame mydata,
splitted using the myindice variable. When I send :
wilcoxtest <- by(mydata, mydata$myindice, function(x)
{wilcox_test(x$value~x$fact)})
I get :
Error in eval(expr, envir, enclos) : object "x" not found
whereas
wilcoxtest <- by(mydata, mydata$myindice, function(x)
2013 Mar 21
2
NADA
Dear Users
Regarding the NADA package, would anyone be able to help me understand what
values are actually plotted on the Y axis of the plot obtained by using the
*ros* function on the data and plotting the result with the plot()
function? The Y axis is labeled "Values". According to the NADA user
manual, ros performs a log transformation of the data by default, but the
user can specify
2010 Aug 17
3
Weird differing results when using the Wilcoxon-test
Hi,
I became a little bit confused when working with the Wilcoxon test in R.
As far as I understood, there are mainly two versions:
1) wilcox.test{stats}, which is the default and an approximation, especially,
when ties are involved
2) wilcox_test{coin}, which does calculate the distribution _exactly_ even,
with ties.
I have the following scenario:
#---BeginCode---
# big example
size = 60
2017 Oct 14
0
Bootstrapped Regression
R-help is not a free coding service. We expect users to make the effort to
learn R and *may* provide help when they get stuck. Pay a local R
programmer if you do not wish to make such an effort.
Cheers,
Bert
On Oct 14, 2017 7:58 AM, "Janh Anni" <annijanh at gmail.com> wrote:
Greetings!
We are trying to obtain confidence and prediction intervals for a predicted
Y value from
2017 Oct 15
0
Bootstrapped Regression
Hello,
Much clearer now, thanks.
It's a matter of changing the function boot calls to return the
predicted values at the point of interess, education = 50, income = 75.
I have changed the way the function uses the indices a bit, the result
is the same, it's just the way I usually do it.
pred.duncan.function <- function(data, indices) {
mod <- lm(prestige ~ education +
2006 Sep 29
1
Wilcoxon Rank test of Package Coin
Hi,
I am running the following example which can be found on page 12 of the pdf file of COIN package
wt<-wilcox_test(pd~age,data=water_transfer,distribution="exact", conf.int=TRUE)
"wt" actually contains the estimate of difference in location and the confidence interval of it. I am just wondering how can I extract these values? From the examples, I understand that the
2013 Apr 17
1
Q-Q Plot for comparing two unequal data sets
Hello All,
Would anyone be able to help me understand how R computes a
quantile-quantile plot for comparing two data samples with unequal sample
sizes? Normally, the procedure should be to rearrange the larger data
sample into n equally-spaced parts using interpolation, where n is the
sample size of the smaller sample, and then plot the matching data pairs. I
tried using different plotting
2011 Jul 08
4
Using t tests
Dear Sir,
I am doing some work on a population of patients. About half of them are
admitted into hospital with albumin levels less than 33. The other half have
albumin levels greater than 33, so I stratify them into 2 groups, x and y
respectively.
I suspect that the average length of stay in hospital for the group of
patients (x) with albumin levels less than 33 is greater than those
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
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
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
2007 Jul 12
1
Subsetting problem
I need to perform the Exact Wilcoxon Mann-Whitney on a subset of my database.
Assuming that IPPO is my data frame and IPPOBIS is the subset my variable still
have 3 different levels and the function wilcox_test (package "coin")
does not accept it.
I do not know how to overcome this problem.
ippo <- c(rep("A",10),rep("B",10),rep("C",10))
ippo2 <-
2009 Nov 01
1
wilcox.test construction in r
Hi, I am very confused with constructing the wilcox.test in R.
I have two populations 'original' and 'test'.
I want to know if the 'test' is generally 'lower' than original.
I use alpha of 0.05.
So do I write the function as wilcox.test(original, test, alternative="l")?
or wlcox.test(original, test, alternative = "g")?
or wilcox.test(test,
2013 Mar 13
4
boxplot
Hi,
I try to boxplot following data on the subset of (V1,V3,V5,V7) and
(V2,V4,V6,V8)
V1 V2 V3 V4 V5 V6 V7 V8
2 4 6 7 12 33 43 53
how can I use boxplot function to plot it?
thanks,
William
2011 Oct 31
2
one sample Wilcoxon test using 'coin'
Hi,
R allows me to run a one sample Wilcoxon test like this:
wilcox.test(c(1,3.5,2.1,4,1.5,5), mu=2, exact=TRUE)
The function 'wilcoxsign_test' from the package 'coin' should (I
suppose) be able to calculate exact p values even if there are ties in
the ranks. However, I couldn't find information on how to run a one
sample test using 'wilcoxsign_test' like in the
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
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