Displaying 20 results from an estimated 10000 matches similar to: "comparing groups of proportions"
2011 Feb 09
2
comparing proportions
Hi, I have a dataset that has 2 groups of samples. For each sample, then
response measured is the number of success (no.success) obatined with the number
of trials (no.trials). So a porportion of success (prpop.success) can be
computed as no.success/no.trials. Now the objective is to test if there is a
statistical significant difference in the proportion of success between the 2
groups of
2011 Sep 27
1
compare proportions
Hi, I have a seemingly simple proportional test. ?here is the question I am trying to answer:
?
There is a test running each day in the lab, the test comes out as
either positive or negative. So at the end of each month, we can calculate a
positive rate in that month as the proportion of positive test results. The
data look like:
?
Month??? ??# positive?????? # total tests??? positive rate
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 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]
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
2008 Mar 28
2
Comparing proportions between groups
Hello there,
I have two groups (men and women) and I know per group how many of them
smoke or don't smoke (women 40 of 200; men 100 of 300). I would like to know
how I can compare in R if men and women differ significantly in their
smoking. However, because there are more men in the sample than women I
cannot just compare the number of smokers and non-smokers in both groups,
right?! (I would
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 <-
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
2013 Jun 30
3
[LLVMdev] [LNT] Question about results reliability in LNT infrustructure
On 06/30/2013 02:14 AM, Anton Korobeynikov wrote:
> Hi Tobi,
>
> First of all, all this is http://llvm.org/bugs/show_bug.cgi?id=1367 :)
>
>> The statistical test ministat is performing seems simple and pretty
>> standard. Is there any reason we could not do something similar? Or are we
>> doing it already and it just does not work as expected?
> The main problem
2010 Jul 14
1
Wilcox.test U values
I have been examining the Mann-Whitney test closely. And there are two
features of the R implementation that puzzles me. The test statistic is
reported as "W" and depends on the order of the arguments to the function.
> x <- c(1,3,5,7,9)
> y <- x-1
> x
[1] 1 3 5 7 9
> y
[1] 0 2 4 6 8
> wilcox.test(x, y)$statistic
W
15
> wilcox.test(y,x)$statistic
W
10
2012 Dec 18
0
R function for computing Simultaneous confidence intervals for multinomial proportions
Dear all,
Does someone know an R function implementing the method of Sison and
Glaz (1995) (see full ref below) for computing Simultaneous confidence
intervals for multinomial proportions?
As alternative method, I think to boostrap the mean of each proportion
and get in that way confidence interval of the mean.
I observed 21 times a response that could be one out of 8 categories
2017 Jun 23
2
Paired Weighted Wilcoxon test in R
Dear R-users,
I?m trying to perform a non-parametric statistical pairwise comparison of two samples "x" and "y" using the Wilcoxon test in R, but each of the pairs have a weight associated.
An example of my data is the following one:
set.seed(9)
x <- sample(x = c(1:100), size = 20, replace = TRUE)
y <- sample(x = c(1:100), size = 20, replace = TRUE)
weight <-
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
2017 Jun 24
0
Paired Weighted Wilcoxon test in R
Hi DC9,
As no one has answered, I would say that as both the survey package
and Professor Lumley are widely respected, that is as good as it gets.
Jim
On Fri, Jun 23, 2017 at 7:26 PM, Dreams Collector
<dreamscollector9 at gmail.com> wrote:
> Dear R-users,
>
> I?m trying to perform a non-parametric statistical pairwise comparison of two samples "x" and "y" using
2010 Jun 23
4
Comparing distributions
I am trying to do something in R and would appreciate a push into the
right direction. I hope some of you experts can help.
I have two distributions obtrained from 10000 datapoints each (about
10000 datapoints each, non-normal with multi-model shape (when
eye-balling densities) but other then that I know little about its
distribution). When plotting the two distributions together I can see
that
2007 Oct 04
1
comparing matched proportions using glm
Dear R users,
Is it possible to use a generalized linear model to do a binomial
comparison of one list of proportions with a matched list of proportions
to test for a difference?
So, for example:
list 1 list 2
a1 | b1 a2 | b2
3 | 4 7 | 9
6 | 7 5 | 1
9 | 1 3 | 1
I want to compare list 1 with list 2 and the samples
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
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?
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
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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