Dear Carmelo, Thanks for the help. We already performed multivariate analyses, but decided to highlight the most important PCs separately as well. I now also performed the residual analysis, suggested by Marcello. Kind regards, Jens
On Tuesday, October 27, 2015 at 12:15:27 AM UTC+1, Carmelo Fruciano wrote: > > Dear Jens, > you might want to consider working with multivariate analyses (i.e. > using all PCs and not a single one) and, as it has been suggested, > using (multivariate) linear models rather than dividing scores by your > size measure. > Best, > Carmelo > > > -- > Carmelo Fruciano > Honorary Fellow - University of Catania - Catania, Italy > e-mail [email protected] <javascript:> > http://www.fruciano.it/research/ > > > > Jens De meyer <[email protected] <javascript:>> ha scritto: > > > Dear, > > > > I have a question about EFDs, and was wondering if you could help > > me? I have performed a PCA on standardized EFDs (standardized for > > first harmonic, using SHAPE-software). The EFDs represented head > > shapes of eels which were given different diets (we compared three > > different diets). The results of the PCA indicated that PC1 was > > related to variation in head width, with high PC-scores being > > related to broader heads and vice versa. Next, we performed a linear > > regression on these PC-scores and log(length) of the three different > > diets and observed a size-effect in all three diets. > > Because of this, I wanted to divide the PC-scores by the total > > length of the studied eels. Then, we would perform an ANOVA on these > > length-corrected PC-scores between the different diets, as this > > would allow us to find out whether the mean head width of a certain > > diet is significantly broader than another diet. > > Therefore, my question to you is: Am I acutally allowed to divide > > these PC-scores by total length? > > Many thanks in advance! > > Kind regards, > > Jens De Meyer > > > > -- > > MORPHMET may be accessed via its webpage at http://www.morphometrics.org > > > > To unsubscribe from this group and stop receiving emails from it, > > send an email to [email protected] <javascript:>. > > > > > > -- > Carmelo Fruciano > Honorary Fellow - University of Catania - Catania, Italy > e-mail [email protected] <javascript:> > http://www.fruciano.it/research/ > > -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
