Statistical analysis: There is substantial evidence supporting the hypothesis of association with exceptional longevity of variants in the three candidate genes chosen here for analysis. This information is presented in this paper. APOE has been replicated as a longevity-determining gene in numerous studies (Christensen et al., 2006). This gene anchors the interaction described in this report (Fig. 5). The hypothesis we test is related to the role of the apolipoprotein APOE in lipid and lipoprotein metabolism. The BioSystems Database (NCBI) lists 228 genes under the entry Metabolism of Lipids and Lipoproteins. APOE and LASS1 are among them. Thus, we assume the prior probability of an interaction of these genes to be 1.0. It is likely that there are genes involved in lipid and lipoprotein metabolism in addition to the 228, and we conservatively propose there to be 300. We, therefore, assume the prior probability of identifying another interacting gene, such as HRAS1, to be 0.01. We set the posterior probability for identification of such a gene at 0.95. Applying Bayes theorem, we obtain the likelihood ratio Pr(Data|Association)/Pr(Data|NoAssociation) of 1881. These considerations are applicable to the initial test of the association with longevity of the combination of the haplotypes in the three genes in both the Georgia and Louisiana populations. The prior probability increases dramatically in subsequent tests, once the deficit accumulation in the Louisiana population is taken into account. The same 0.01 frequency cutoff was applied. This involved adjustment for up to two comparisons, using the sequential Dunn-Sidak procedure. The haplotype combination frequencies differed significantly in the various samples examined. These haplotypeLi L, Kim S, Kimball B, Jazwinski SM, Arnold J, for the Georgia Centenarian Study. Exact sample size needed to detect dependence in x x tables. Biometrics. 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