[R] mantel tests

Mark Difford mark_difford at yahoo.co.uk
Sun Nov 4 11:22:02 CET 2007


Hi Simon,

>> This is a general statistics question so I'm sorry if its outside the
>> field of r help.
>> Could anyone please provide a starting point?

This doesn't directly answer your question, but one thing I would do is get
ade4 and look at Chessel's co-inertia analysis method.  It's a very general,
and robust, method.  It would involve treating your male and female trait
tables separately, and then matching then (usually after a PCA).  The method
is "based" on (or uses) Robert & Escoufier's RV-coefficient, and looks at
the covariance between the two matrices.

See:
Dray, S., Chessel, D. and J. Thioulouse (2003) Co-inertia analysis and the
linking of the ecological data tables. Ecology, 84, 11, 3078–3089
http://biomserv.univ-lyon1.fr/~dray/files/articles/SD162.pdf

There is an excellent plot method, which should give you good insight, and
there is a method for doing Monte-Carlo permutation tests of the match.

I hope this is useful.

Regards,
Mark Difford.


Simon Pickett wrote:
> 
> This is a general statistics question so I'm sorry if its outside the
> field of r help.
>  
> Anyway, I have a suite of female and male traits and I have made a matrix
> of correlation coefficients using rcorr(). This results in a 6 by 6 matrix
> like this..
>  
> [1] 0.11287990 0.20441361 0.23837442 0.04713234 0.04331637 0.01461611
>  [7] 0.22627981 0.11720108 0.14252307 0.19531625 0.29989953 0.09989502
> [13] 0.03888750 0.11157971 0.02693303 0.01373447 0.08913154 0.06770636
> [19] 0.01984838 0.10047978 0.05200218 0.16317234 0.26999963 0.10412373
> [25] 0.06269722 0.14366454 0.13123054 0.27550149 0.43863848 0.28909831
> [31] 0.01454485 0.02551081 0.05645427 0.15819397 0.16508231 0.12399349
> 
> I want to test 2 hypotheses
>  
> 1) is there a pattern to the matrix, does it differ from random?
> 2) do the top left and bottom right quadrants differ from the other 2
> quadrants and if so, which one has the highest values of r2.
>  
> I have read alot about permutation tests, bootstrapping and mantel tests
> but cant decide which is best in this situation? 
>  
> Could anyone please provide a starting point?
>  
> Thankyou in advance, Simon
> 
> 	[[alternative HTML version deleted]]
> 
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