Table 3.

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

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%