[R] Letter-based representation of pairwise comparisons

[retama]

Hello:

That's because the required input should be a symmetric matrix with all the
comparisons, e.g., it should have the self-comparisons diagonal. In an
hypotetical case with two treatments, the pairwise-comparison test output is
something like that:

        A B 
B 0.80    -     

but multcompView requires an input like that one:

 A B 
A 1 - 
B 0.80 1   

That means you should add a new row and column for your missing treatments
and, then, a diagonal of "1"s meaning that each treatment compared with
itself will result in a p-value of 1 (maximal identity). Then, the new
matrix could be piped succesfully.

Regards,

Retama


goz wrote:
> 
> hello,
> 
> i try to use the multcomp letters, but i have problems with my results : 
> 
> here is my pvalue matrix (from a pairwise.t.test) : 
> 
> pair=pairwise.t.test(...)
> pair$p.value
> 
>         0           B            BxS    
> B    0.01727    -             -      
> BxS 0.00013    0.00226   -      
> S    0.87555    0.02610   0.00027
> 
> 
> i was thiking to have something like that : 
>  0  B  S  BxS
>  a  b  a  c
> 
> but function return : 
> 
>> multcompLetters(pair$p.value)
>   B   BxS   S 
>  "a"  "b"   "a" 
> 
> 
> first question : why the 0 traitement doesn't appears in result ?
> second  : why the results differs than what i expected ?
> 
> many thanks.
> 
> 

-- 
View this message in context: http://www.nabble.com/Letter-based-representation-of-pairwise-comparisons-tp21350364p25769894.html
Sent from the R help mailing list archive at Nabble.com.