Re: size correction discriminant functions analyses

2004-05-19 Thread morphmet
Dear Brett, If the problem is separating size and shape, then, fortunately, in my edited book titled Morphometrics- Applications in Biology and Paleontology (Springer-Verlag, 2004) you will find a chapter that is written by Garcia-Rodriguez et al. They used the Sheared PCA analysis and could

Re: size correction discriminant functions analyses

2004-05-19 Thread morphmet
There is a method called common PCA which seems to overcome the problem of non-multinormality of overall sample that includes several subsamples all with different central momenta. The source to read is: Flury B. 1988. Common principal components and relatÃ…d multivariate models. NY: Wiley. 258 p.

Re: size correction discriminant functions analyses

2004-05-19 Thread morphmet
Just a comment on this one, from a pragmatic point of view. It is of course true that PCA is only *guaranteed* to produce components maximizing variance if you have multivariate normality. The theory of PCA is based on this assumption. But in many cases, PCA is used purely as a visualization