I don't know about how to do it in PAST, but note that because the slope of the standard major axis "regression" line is just the signed ratio of two standard deviations, its square follows the F-distribution if one assumes that the two variances are based on random samples from two normally distributed populations. Thus a test for a slope = 1 corresponds to a 2-tailed test for the equality of variances. One can easily look up probabilities in an F-table or compute confidence limits using standard methods. Note that if the samples are across different populations or species, as in many (most?) morphometric applications, then these assumptions do not hold.
____________________________________________ F. James Rohlf, Distinguished Professor, Emeritus. Ecology & Evolution Research Professor, Anthropology Stony Brook University -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Patrick Arnold Sent: Saturday, March 12, 2016 4:49 AM To: [email protected] Subject: [MORPHMET] model II regression statistics PAST Dear morphometrics, I am frequently using PAST (paleontological statistics; what a great free software) for the analysis of morphometric data (geometric and traditional). Now I want to do a reduced major axis regression on bivariate data (only one Y for each X). However, I do not found the possibility to perform a significance test for the regression (F statistics) or for the slope and intercept (t statistics). It is provided for least square regression (e.g., under polynomial option) but not for model II regression. Does anyone know a possibility to obtain regression statistics in PAST for model II regressions? Thanks in advance. Cheers Patrick -- Patrick Arnold, M.Sc. wissenschaftlicher Mitarbeiter und Doktorand Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem Museum Friedrich-Schiller-Universität Jena Erbertstraße 1 07743 Jena Germany Phone: +49 (0)3641 9-49165 Fax: +49 (0)3641 9-49142 E-mail: [email protected] -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- You received this message because you are subscribed to the Google Groups "MORPHMET" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- You received this message because you are subscribed to the Google Groups "MORPHMET" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
