-------- Original Message -------- Subject: RE: CVA and MANOVA Date: Thu, 28 Feb 2008 09:37:07 -0800 (PST) From: [EMAIL PROTECTED] To: [email protected]
Hi, The complication with CVA in estimation of shape configurations is that CVA distorts the original tangent space of shapes were parametric analyses are often applied. There is an interesting paper discussing this aspect: Klingenberg, C. P. and L. R. Monteiro. 2005. Distances and directions in multidimensional shapes spaces: implications for morphometric applications. Systematic Biology 54(4):678-688. However, some friends in the forum have already suggested interesting options on how to estimate shape configurations in the context of CVA. As for the possible problem of using multivariate vectors (relative warps) rather than the original variables (part warps), in statistical contrast tests (CVA-MANOVA), I think Dr. Rohlf has already made clear how relative warps are nothing more than statistically orthogonal (independent) linear combinations of the original variables. Hence, there is no "non-independence data problem" if using RW for a MANOVA. Problems may be found when you have collinearity or sphericity among the original variables; then you will have a sort of non-independence, something a factor analysis could resolve. Good luck Pablo Pablo Jarrin Grad student Dept. of Biology Boston University -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
