1. From the Department of Psychology (P.K.E., M.F.E., M.A.R), University of Maine, Orono; Statistics and Consulting Unit (P.K.E., M.F.E.), Department of Mathematics and Statistics, Boston University, Boston, Mass; Department of Geriatric Medicine (M.M.B), ANU Medical School, The Canberra Hospital, Woden ACT, Australia.