Hi all,
I have a statistical problem that I can't resolve. I have measured morphometric variabilty in populations of Australian bass from seven locales throughout this species range. Both univariate and multivariate tests indicate that the collections exhibit significant morphological variation. From a discriminant function analysis I have derived pairwise Mahalanobis squared distances between locales and now want to test to see which collection centroids indicated by these squared distances are significantly different. After much searching I have come up with an Ftest reputed to test these distances. The only problem is that the authors neglected to mention what one of the symbols in the equation means. Can anybody suggest what the p in the following equation relates to? I suspect it is the number of variables entered into the discriminant function but I am not sure. The equation is:
F (p, n  g  p + 1) = D2 * (1/nA + 1/nB)1 * (n  p  1)/p (n  g), where D2 is Mahalonobis squared distance, nA is the number of observations in collection A, n is the total number of observations, and g is the number of groups. This Ftest comes from
J.M. McGlade and E.G. Boulding. 1986. The truss: A geometric and statistical approach to the analysis of form in fishes. Canadian Technical Report of Fisheries and Aquatic Sciences No 1457.
Thanks in advance,
Dean Jerry Dean Jerry Animal Conservation Genetics Southern Cross University Lismore NSW 2480 Australia Ph: 61 66 203815 Fax: 61 66 212669 **************************************************************************** If we possessed a thorough knowledge of all parts of the seed of any animal, we could from that alone, by reasons entirely mathematical and certain, deduce the whole conformation and figure of each of its members, and, conversely if we knew several peculiarities of this conformation, we would from those deduce the nature of its seed. Rene` Descartes 15961650 (Oeuvres iv, 494) ****************************************************************************
