R help - Jan 2009 - Letter-based representation of pairwise comparisons

Hi!

I have been working several years with R but it's my first public question.
I hope I'll be clear :) .

This question is related to obtaining letter-based representation of
non-parametric pairwise comparisons.

I have a dataframe with this structure (but with quite more rows and cols):

A B C  factor
1 2 2 one
2 1 2 one
2 2 3 two
2 3 2 two
1 4 2 three
9 8 1 three

I have no normality, so I did a kruskal test which showed significant
differences in some cases. As post hoc pairwise comparisons (the idea is to
make an equivalent to Tukey test after an ANOVA) I tried with a paired
wilcoxon test with the Bonferroni's correction (pairwise.wilcox.test(A,
factor, p.adj="bonf") and other for B, and so on) and, now, I need to
modify
the output to show a letter-based representation of all pairwise
comparisons. Some algorithms have been published
(http://www.accessmylibrary.com/coms2/summary_0286-21655824_ITM), but I
can't find an R implementation.

Does anyone know how to do that?

Thank you!!

Retama
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On Thu, Jan 8, 2009 at 5:40 AM, retama <retama1745 at gmail.com>
wrote:
>
> Hi!
>
> I have been working several years with R but it's my first public
question.
> I hope I'll be clear :) .
>
> This question is related to obtaining letter-based representation of
> non-parametric pairwise comparisons.
>
> I have a dataframe with this structure (but with quite more rows and cols):
>
> A B C  factor
> 1 2 2 one
> 2 1 2 one
> 2 2 3 two
> 2 3 2 two
> 1 4 2 three
> 9 8 1 three
>
> I have no normality, so I did a kruskal test which showed significant
> differences in some cases. As post hoc pairwise comparisons (the idea is to
> make an equivalent to Tukey test after an ANOVA) I tried with a paired
> wilcoxon test with the Bonferroni's correction (pairwise.wilcox.test(A,
> factor, p.adj="bonf") and other for B, and so on) and, now, I
need to modify
> the output to show a letter-based representation of all pairwise
> comparisons. Some algorithms have been published
> (http://www.accessmylibrary.com/coms2/summary_0286-21655824_ITM), but I
> can't find an R implementation.
http://cran.r-project.org/web/packages/multcompView/ ?

Hadley

-- 
http://had.co.nz/