Figure 6

Three omnidirectional semivariograms of breast cancer mortality rates with the model fitted. This graph was created by poisson_kriging.exe using the parameter file of Figure 3 with the option ndir = 1. The estimators are the followings: traditional semivariogram (Equation 8 with n(u_α) = 1 ∀ α), population-weighted semivariogram (Equation 8), and risk semivariogram (Equation 18). The solid curve denotes the model fitted using weighted least-square regression.