Fig. 5

Combined population and areal weighting. The geographic area of the tract within the zone, the areal weight (A _zt /A _t ), is multiplied by population-weighted mortality estimate for the tract (E _mt ). The output for each tract is then summed to estimate the number of deaths for the zone. We demonstrate, in this example, how estimates for portions of zones A and B are calculated. Note: As illustrated in Figs. 3 and 4, except for two counties, with two deaths each, the remaining counties within zones A and B recorded zero deaths for the population of interest; to simplify the illustration, we omitted counties with zero deaths. Also, because we show only portions of zones A and B, the estimates are technically only a portion of M _z for zones A and B