Figure 3

Probability of the local Q statistic at k = 7 not accounting for smoking, age, gender, race and education (x axis) versus the probability of the local statistic accounting for smoking and these covariates (y axis). The 20 points in the lower left quadrant are centers of significant case clusters even after smoking and the four covariates are accounted for. The 6 points in the lower right quadrant were cases that have become significant after covariate adjustment. 4 cases were significant before covariate adjustment but not afterwards.