-------- Original Message -------- Subject: Calculating Consensus Shapes Date: Thu, 13 Mar 2008 14:37:58 -0700 (PDT) From: Greiner Thomas <[EMAIL PROTECTED]> To: <[email protected]>
When comparing shapes among different groups we usually reference each individual, or the consensus shape of each group, to the grand consensus shape of the data pool. But, what do we do if our groups are of grossly unequal sample sizes? If this were a univariate problem I would be tempted to use weighted means for each group. But, how do we do this with multivariate shape data? Is it important to account for sample size differences when calculating PCA scores? What about when creating the spline deformation grids? Do the common programs that provide consensus shapes already account for potential sample size differences? Is this not as big a problem as I am thinking it might be (I've got groups with sample sizes ranging from 300 to 20)? */Thomas M. Greiner, Ph.D./* Anatomist and Physical Anthropologist Dept. of Health Professions University of Wisconsin - La Crosse 1725 State Street La Crosse, WI 54601 USA Phone: (608) 785-8476 Fax: (608) 785-8460 -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
