[R] How to apply the Wilcoxon test to a hole table at once?

[Iurie Malai]

Thank you very much!

This is my adapted script and now it is OK:

>lapply(Dataset[3:17], function(x) wilcox.test(x ~ X2,
alternative="two.sided", data=Dataset))

But it is possible to get results more compact, similar to a table?

Iurie Malai
Moldova Pedagogical State University


Steven McKinney wrote:
> 
> 
>> -----Original Message-----
>> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
>> project.org] On Behalf Of Iurie Malai
>> Sent: Friday, October 23, 2009 10:46 AM
>> To: r-help at r-project.org
>> Subject: [R] How to apply the Wilcoxon test to a hole table at once?
>> 
>> 
>> Hi,
>> 
>> I have a data set:
>> 
>> > Dataset
>>      X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15 X16 X17
>> 1 user1  m 22 19 28 24 12 18  9   7   4   5   4   7   5   7   9
>> 2 user2  f 25 19 23 18 18 15  6   8   6   6   7  10   7   7   7
>> 3 user3  f 28 21 24 18 15 12 10   6   7   9   5  10   5   9   5
>> 4 user4  f 26 19 26 21 12 18  6   6   5   1   3   8   6   5   6
>> 5 user5  m 21 22 26 18  9  6  4   6   1   7   2   4   4   6   4
>> 6 user6  m 24  8 25 12 18 12  7   8   4   1   4   6   7   5   6
>> ...............................................................
>> 71 user71  m 18  4 10  6  3  6  9   5  10   8   4   5   6   5   5
>> 
>> I can apply the Wilcoxon test on each column one by one, but how to do
>> this
>> on the hole table at once?
>> 
>> > wilcox.test(X3 ~ X2, alternative="two.sided", data=Dataset)
>> 
>> 	Wilcoxon rank sum test with continuity correction
>> 
>> data:  X3 by X2
>> W = 439, p-value = 0.1291
>> alternative hypothesis: true location shift is not equal to 0
>> 
>> >
> 
> Here's one way to do it (using airquality dataset)
> 
>> lapply(airquality[1:4], function(x) wilcox.test(x ~ Month,
>> alternative="two.sided", data=airquality, subset = Month <= 6))
> $Ozone
> 
>         Wilcoxon rank sum test with continuity correction
> 
> data:  x by Month 
> W = 82, p-value = 0.1925
> alternative hypothesis: true location shift is not equal to 0 
> 
> 
> $Solar.R
> 
>         Wilcoxon rank sum test with continuity correction
> 
> data:  x by Month 
> W = 391.5, p-value = 0.8354
> alternative hypothesis: true location shift is not equal to 0 
> 
> 
> $Wind
> 
>         Wilcoxon rank sum test with continuity correction
> 
> data:  x by Month 
> W = 566, p-value = 0.1461
> alternative hypothesis: true location shift is not equal to 0 
> 
> 
> $Temp
> 
>         Wilcoxon rank sum test with continuity correction
> 
> data:  x by Month 
> W = 78, p-value = 2.400e-08
> alternative hypothesis: true location shift is not equal to 0 
> 
> 
> Warning messages:
> 1: In wilcox.test.default(x = c(41L, 36L, 12L, 18L, 28L, 23L, 19L,  :
>   cannot compute exact p-value with ties
> 2: In wilcox.test.default(x = c(190L, 118L, 149L, 313L, 299L, 99L,  :
>   cannot compute exact p-value with ties
> 3: In wilcox.test.default(x = c(7.4, 8, 12.6, 11.5, 14.3, 14.9, 8.6,  :
>   cannot compute exact p-value with ties
> 4: In wilcox.test.default(x = c(67L, 72L, 74L, 62L, 56L, 66L, 65L,  :
>   cannot compute exact p-value with ties
>  
> # Sanity check:
>> wilcox.test(Temp ~ Month, alternative="two.sided", data=airquality,
>> subset = Month <= 6)
> 
>         Wilcoxon rank sum test with continuity correction
> 
> data:  Temp by Month 
> W = 78, p-value = 2.400e-08
> alternative hypothesis: true location shift is not equal to 0 
> 
> Warning message:
> In wilcox.test.default(x = c(67L, 72L, 74L, 62L, 56L, 66L, 65L,  :
>   cannot compute exact p-value with ties
>>
> # Same as lapply loop result
> 
> 
> HTH
> 
> Steven McKinney
> Statistician
> Molecular Oncology and Breast Cancer Program
> British Columbia Cancer Research Centre
> 
> 
> 
> 
> 
>> 
>> I researched on this, but I can't find a solution.
>> I would really appreciate any help.
>> 
>> P.S. Excuse my lack of terminology :).
>> 
>> Iurie Malai
>> Moldova Pedagogical State University
>> --
>> View this message in context: http://www.nabble.com/How-to-apply-the-
>> Wilcoxon-test-to-a-hole-table-at-once--tp26030572p26030572.html
>> Sent from the R help mailing list archive at Nabble.com.
>> 
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide http://www.R-project.org/posting-
>> guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

-- 
View this message in context: http://www.nabble.com/How-to-apply-the-Wilcoxon-test-to-a-hole-table-at-once--tp26030572p26036377.html
Sent from the R help mailing list archive at Nabble.com.