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Table 3 Z-Test results for discrete buffer analysis. Results labeled with * are significant using p < 0.01.

From: Improving environmental exposure analysis using cumulative distribution functions and individual geocoding

Buffer radius (miles) 0.25 0.5 1 2 4
Gasoline stations:
Geocoded home locations:
   School 13.02% 26.37% 63.45% 92.32% 99.18%
   Home 8.20% 28.63% 66.37% 88.01% 97.76%
   Difference 4.82%* -2.26%* -2.92%* 4.31%* 1.42%*
Tract centroid:
   School 13.02% 26.37% 63.45% 92.32% 99.18%
   Home 2.71% 17.57% 60.56% 83.56% 89.78%
   Difference 10.31%* 8.80%* 2.90%* 8.76%* 9.41%*
BG centroid:
   School 13.02% 26.37% 63.45% 92.32% 99.18%
   Home 3.63% 20.97% 61.57% 85.14% 95.92%
   Difference 9.39%* 5.40%* 1.88%* 7.18%* 3.26%*
AIRS facilities:
Geocoded home locations:
   School 5.58% 16.87% 53.44% 84.36% 97.95%
   Home 6.76% 25.20% 56.30% 82.57% 97.86%
   Difference -1.18%* -8.33%* -2.86%* 1.79%* 0.08%
Tract centroid:
   School 5.58% 16.87% 53.44% 84.36% 97.95%
   Home 1.44% 14.45% 57.04% 80.28% 97.60%
   Difference 4.14%* 2.42%* -3.60%* 4.08%* 0.34%*
BG centroid:
   School 5.58% 16.87% 53.44% 84.36% 97.95%
   Home 2.88% 17.80% 57.16% 81.46% 97.23%
   Difference 2.70%* -0.93%* -3.72%* 2.90%* 0.72%*
TRI facilities:
Geocoded home locations:
   School 0.18% 0.79% 6.01% 30.29% 70.73%
   Home 0.34% 1.55% 7.78% 28.52% 70.71%
   Difference -0.16%* -0.76%* -1.78%* 1.77%* 0.03%
Tract centroid:
   School 0.18% 0.79% 6.01% 30.29% 70.73%
   Home 0.55% 3.23% 6.95% 30.54% 70.09%
   Difference -0.37%* -2.44%* -0.95%* -0.25% 0.64%*
BG centroid:
   School 0.18% 0.79% 6.01% 30.29% 70.73%
   Home 1.20% 3.40% 6.69% 31.32% 69.72%
   Difference -1.02%* -2.62%* -0.69%* -1.03%* 1.02%