[R] Dunn's post hoc test

[Martin Henry H. Stevens]

I don't know Dunn's rank test, but the following substracts each of  
the sums of averanks from the next rank.

cumsum(averank)[-length(averank)] - averank[-1]

Hank

On Oct 17, 2005, at 4:30 AM, Iain Gallagher wrote:

> Hi Everyone.
>
> I am rather new to R and I've been trying to implement a function to
> carry out the above test. For a couple of days now I've been stuck on
> how to generate average rank differences.
>
> Say I have a vector of average ranks:
>
> averank<- c(2,5,9,12)
>
> I would like to subtract averank[1] from averank[2], averank[1] and
> averank[2] from averank[3] and averank[1], averank[2] and averank[3]
> from averank[4] etc (I know the syntax is wrong here... it's just for
> illustration) but I can't work out how to do it.
>
> Ideally I would like to generate an array showing the differences
> between the average ranks so I could tell at a glance which ones were
> greater than my critical value
>
> I've been looking at loops etc but it's a little beyond me at the
> moment. Thanks for any suggestions.
>
> Iain Gallagher
> IIIR
> Edinburgh University
>
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Dr. Martin Henry H. Stevens, Assistant Professor
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