Dear morphometricians, I am using tests for common slopes and homogeneity of intercepts, as explained by Prof. Rohlf in TPSRegr, for comparing allometric trajectories during post-natal ontogeny of different species. My impression is that these tests are very powerful and detect even small differences in slopes or intercepts. However, I suspect that it may be often interesting if the amount of differences among ingroup species (say, belonging to the same genus) could be compared to differences in allometric trajectories between the ingroup species and an outgroup species (for instance, a species of a different but closely related genus). Any suggestion, please? Id also be curious to know whether or not you would try to take into account the fact the samples are not statistically independent because of taxonomic hierarchy when performing these tests.
A second, related, question. What are the possible biological interpretations of having trajectories with similar slopes but different intercepts? (Differences arising early, i.e. before birth, in development??? Other interpretations?). Thanks a lot, in advance, for your help. Best Andrea Andrea Cardini Istituto di Medicina Legale e delle Assicurazioni Universit degli Studi di Milano via Mangiagalli 37 Milano 20133, Italy tel. 0039 02 50315678/9 [EMAIL PROTECTED] and Division of Mammals, Department of Vertebrate Zoology NHB 390, MRC 108 National Museum of Natural History, Smithsonian Institution P.O. BOX 37012 Washington, DC 20013-7012, USA tel. 202 3571476 [EMAIL PROTECTED] -------------------------------------------------------------------------- CONCORSO "All Friends": NAVIGA CON INTERFREE E VINCI OLTRE 5.000 PREMI HI.TECH! Iscriviti gratuitamente all'indirizzo http://promo.interfree.it naviga in internet con i nostri numeri a tariffa urbana e vinci: 3.000 Mouse ottici 1.200 Mouse ottici per notebook 600 Mouse wireless 300 Tastiere wireless + mouse wireless 150 Sistemi wireless access point completi di due pcmci card 60 Monitor LCD da 15" 18 Notebook BUONA FORTUNA! ;-) Lo Staff di Interfree -------------------------------------------------------------------------- == Replies will be sent to list. For more information see http://life.bio.sunysb.edu/morph/morphmet.html.
