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Vegetation cluster testing using MRPP

Curt Seeliger cws1 at dirt.first!
Mon May 18 09:22:38 EST 1998

Folks,  I'm currently at a loss.  I'm developing vegetation types using
standard hierarchic clustering techniques (Euclidian distance, Ward's
method).  I'm testing these groups using Multiple-Response Permutation
Procedures, which estimates the likelyhood of finding tighter clusters. 
MRPP results in p-values ranging from 0.0002 to 0.90 for clusters derived
in this manner, depending on how I transform the data matrix before

My problem is that groupings which are statistically significant do not
appear to be of any ecological meaning.  I'm fairly boggled by these
results, as I would assume that any sort of clustering method would always
produce groupings which are at least better than random (p < 0.50), but
this does not seem to be the case.

Any help would be appreciated.  Thanks.


 DIRT   /\   FIRST! |  Curt Seeliger
       /  \         |  Humbled State University
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