Janh,
Janh Anni skrev 2013-06-01 04:27:
Hello peter,
Thanks for the comment. wilcox.exact is simpler as you pointed out but the
fact that it is no longer being developed is somewhat concerning.
Admittedly, 'coin' is being actively developed and has a lot more bells
and whistles. But for something as simple as this, that wouldn't bother
me at all. In any case, the 'exactRankTests' package still gets bug
fixes and the algorithm used in the Wilcoxon case is exactly the same
for both packages.
However, if you want to stay with 'coin' you can just wrap up Greg's
proposal in a function:
wilcox_test.default <- function(x, y, ...) {
data <-
data.frame(values = c(x, y),
group = rep(c("x", "y"), c(length(x), length(y))))
wilcox_test(values ~ group, data = data, ...)
}
Assuming that both 'coin' and 'exactRankTests are loaded, we can now
check that it works:
> set.seed(123)
> x <- rpois(10, 3)
> y <- rpois(11, 3.1)
>
> wilcox_test(x, y, alternative = "less", distribution = "exact")
Exact Wilcoxon-Mann-Whitney Test
data: values by group (x, y)
Z = -0.0715, p-value = 0.4844
alternative hypothesis: true mu is less than 0
> wilcox.exact(x, y, alternative = "less")
Exact Wilcoxon rank sum test
data: x and y
W = 54, p-value = 0.4844
alternative hypothesis: true mu is less than 0
HTH,
Henric
Regards
Janh
On Fri, May 31, 2013 at 6:50 PM, Peter Ehlers <ehl...@ucalgary.ca> wrote:
On 2013-05-30 20:20, Janh Anni wrote:
Hello Greg,
Thank you so much for your kind assistance. It looks like there's no way
around using the formula format. I longed in vain for a simpler script
more like the wilcox.test format. Thanks again.
Janh
I don't see why the formula syntax would be a problem, but to avoid it
you could use exactRankTests::wilcox.exact() which, I believe, was
written by the same author. It uses the same syntax as wilcox.test().
Note, though, that the package is no longer
being developed.
Peter Ehlers
On Thu, May 30, 2013 at 6:21 PM, Greg Snow <538...@gmail.com> wrote:
Ok, it looks like the function mainly works through the formula syntax.
It still would have been nice to have a reproducible example of what
your
data may look like, but I can show an example with simulated x and y:
x <- rpois(10, 3)
y <- rpois(11, 3.1)
mydf <- data.frame( vals = c(x,y),
+ group=rep( c('x','y'), c( length(x), length(y) ) ) )
wilcox_test( vals ~ group, data=mydf )
Asymptotic Wilcoxon-Mann-Whitney Test
data: vals by group (x, y)
Z = -1.3718, p-value = 0.1701
alternative hypothesis: true mu is not equal to 0
Does that help? (maybe I am the heedlessness theorist after all)
On Thu, May 30, 2013 at 4:14 PM, Janh Anni <annij...@gmail.com> wrote:
I thought (hoped) wilcox_test(x,y) would do it but it doesn't and the
package maintainer says the data have to be rearranged but does not
specify
how. Thanks
Janh
On Thu, May 30, 2013 at 6:05 PM, Greg Snow <538...@gmail.com> wrote:
What have you tried so far? Have you read the help page? have you run
the examples on that page?
I would expect that it is something as simple as
library(coin)
wilcox_test(x,y)
or
wilcox_test( y ~ group )
But you should trust the help page more than the expectations of
someone
who has not read it recently (see fortune(14)).
If that does not answer your question then give us more detail on what
you tried, what you expected the results to be, what the results
actually
were, and how they differed. Without that information we have to
resort to
mind reading and the current implementation of the esp package is still
very pre-alpha, it suggests that the answer to your question is:
esp()
[1] "selflessly vigilantly pigeon theorist heedlessness"
Which is either much to profound for the likes of me to understand or
is
complete gibberish (which is only slightly less helpful than an overly
general question without a reproducible example).
On Thu, May 30, 2013 at 2:07 PM, Janh Anni <annij...@gmail.com> wrote:
Dear All,
I have two simple data samples (no groups or factors, etc.) and would
just
like to compute the two-sample Wilcoxon Rank Sum test using the
wilcox_test
function contained in the coin package, which is reportedly better
than
the
regular wilcox.test function because it performs some adjustment for
ties.
Would anyone know how to craft a script to perform this task? Much
appreciated.
Janh
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538...@gmail.com
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