-------- Original Message -------- Subject: Re: more CVA and LDF Date: Wed, 22 Oct 2008 06:55:59 -0600 From: [EMAIL PROTECTED] To: morphmet <[EMAIL PROTECTED]> Another reference for a discussion on DA and CVA is Neff, NA & Marcus, LF (1980) "A survey of multivariate methods for systematics" Cheers, Martin Quoting morphmet <[EMAIL PROTECTED]>:
-------- Original Message -------- Subject: more CVA and LDF Date: Fri, 17 Oct 2008 01:59:31 -0700 (PDT) From: Fabio de Andrade Machado <[EMAIL PROTECTED]> To: [email protected] Hi all, Sorry to bring this up once more, but I don´t think any response on that have been posted (recently) on the list. What are the key differences of Canonical Variate Analysis and Linear Discriminant Functions? On Pete E. Lestrel´s "Morphometrics for the Life Science" it reads "A discriminant function is a linear equation, one per individual specimen, derived from the set of original variables x1, x2, x3, ...., xn, each of which is multiplied by a 'weighting' coefficient, a1,a2,a3,...,an (...). A set of these discriminant functions (...) is then computed for each individual case. Each discriminant function score is orthogonal with respect to all others". (p. 159-160) About Canonical Variate Analysis he says that it is design to calculate "[1](...) the correlation between two derived variables and [2] a set of canonical variates or canonical functions (as suns of weighted variables)(...)" (p.161). About both he says "Although displayed results are indistinguishable in many respects, the purpose are different" (p.160), being the CVA basically an graphical aid for LDF. Can anyone send some references on the specifics of each method? They seem distinct somehow. On R there are two different functions, being the one associated with CVA basically for graphical purposes (which is confusing, as the one can display graphically the results of discriminant functions and they seem basically the same). cheers, -- Fabio de Andrade Machado Laboratorio de Herpetologia/Morfometria Museu de Zoologia da USP Av. Nazaré, 481, Ipiranga São Paulo, SP, 04263-000 Brazil +55 11 61658120 +55 11 82631029 -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
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