Nicolas Bailly Bailly at CIMRS1.MNHN.FR
Tue Jun 13 11:42:56 CDT 1995

On Mon, 12 Jun 1995 11:39:42 -0400, Warren Lamboy wrote

>In my opinion, a good way to quantify one's confidence in a determination is
>by comparison to known standards, that is, by statistical comparison to
>specimens whose identities are known.  There are a number of ways to do this,
>but one way, with which I am familiar is that of disjoint principal component
>analysis (Systematic Botany 1990, Vol.15:3-12) which was first developed by
>Dr. Svante Wold, of the University of Umea, Umea, Sweden.
The problem with many statistical analysis is that the data MUST match some known distribution, more or less following the robustness of the method. And the less they match it, the less the interpretations are accurate.

Moreover, the traditionnal normal and lognormal distributions seem to me

not always                <<<-----------              To be
not often                <<<-----------               choosen

adjusted for biological problems. Even if PCA is robust face to the data normality, I guess these kinds of data are too far of the normality.

I think the problem of confidence is relevant to the fuzzy logic (theory of possibilities), not to the statistics (theory of probabilities).

Nicolas Bailly
Museum National d'Histoire Naturelle,
Laboratoire d'Ichtyologie Generale et Appliquee
43, rue Cuvier, 75231 Paris Cedex 05, France
Tel: (33 1) 40 79 37 63   /   40 79 37 49   Fax: 40 79 37 71
Telex: MUSNAHN 202 641 F           E-Mail:    bailly at

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