R help - Oct 2008 - Saving kruskal wallis p-values

Hi everyone, 

I am working on analyzing spectra which requires hundreds of kruskal wallis 
tests to be performed. Once significant results are found post tests are 
performed ect. My questions are: how do I perform all these kw tests and 
save just the pvalues in a table? Is there anyway to have R automatically 
perform post tests if a result of p<0.05 is found? Currently when I run the 
test for one point on the spectra these are the results I get:

Kruskal-Wallis rank sum test

data:  X175 by treatment 
Kruskal-Wallis chi-squared = 22.9769, df = 9, p-value = 0.006249

Any help on this would be appreciated. I am just trying to streamline all 
this analysis.

Thanks
Candice

Those are the results that print, not what you get.  Try saving the results of
the test in an object, then examine the saved object with the str function. 
Then reread the section in "An Introduction to R" on extracting pieces
of lists.  A reread of the help page for kruskal.test, specifically the Value
section, would also be a good idea.

--
Gregory (Greg) L. Snow Ph.D.
Statistical Data Center
Intermountain Healthcare
greg.snow at imail.org
801.408.8111

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of lave0083 at umn.edu
> Sent: Wednesday, October 22, 2008 9:18 AM
> To: r-help at r-project.org
> Subject: [R] Saving kruskal wallis p-values
>
> Hi everyone,
>
> I am working on analyzing spectra which requires hundreds of kruskal
> wallis
> tests to be performed. Once significant results are found post tests
> are
> performed ect. My questions are: how do I perform all these kw tests
> and
> save just the pvalues in a table? Is there anyway to have R
> automatically
> perform post tests if a result of p<0.05 is found? Currently when I run
> the
> test for one point on the spectra these are the results I get:
>
> Kruskal-Wallis rank sum test
>
> data:  X175 by treatment
> Kruskal-Wallis chi-squared = 22.9769, df = 9, p-value = 0.006249
>
> Any help on this would be appreciated. I am just trying to streamline
> all
> this analysis.
>
> Thanks
> Candice
>
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