Multivariate Discriminant Function Analyses of the Mandible in American Caucasoid and American Negroid Populations

The purpose of this thesis is to develop a statistical method whereby the race and sex of an unknown individual may be ascertained from measurements taken from the mandible alone. Twenty-five such measurements were obtained from 160 mandibles representing, equally, American male and female Negro and Caucasian individuals. The skeletal collection used was the Terry collection at the Smithsonian Institution in Washington, D.C.

The data obtained were analyzed by nine separate discriminate functions representing various aspects of the mandible, including one which discriminated the samples by race only.

To test the significance and reliability of using such a procedure for forensic purposes, 13 test specimens were obtained from the University of Tennessee Anthropology Department forensic cases. These were subjected to discriminant function analysis which correctly identified anywhere from 38.5% to 76.9% of them (as opposed to a classification range of 37.5% to 97.5% in the reference samples themselves).

Further, using the discriminant function which classified only race, a test was set-up to ascertain the reliability of using such skeletal collections as the Terry samples to obtain data for use in establishing discriminant functions which test mandibular specimens from groups which may be temporally or genetically removed from the reference samples.