range combinations in the first sPCA component of the 1000 bootstrap samples determined, as well as the frequency of occurrence of the significant and non-significant SNP-age range combinations from the actual sample. The 95th percentile of cumulative distribution function of the fraction of the occurrences of each of the members of the 99 members non-significant group in the sparse PCA across the bootstrap sample acts as the criterion for significance at the .05 level; every snp-age range combination which occurs in a greater fraction of bootstrap instances than that of the significance criterion is found to be significant. This is an adaptation of the method described in Efron (2008).
