Table 1.

Linear regression analysis of estimated and true values for β₁.

Independent variable	Estimate (95% CI)	S.E	P value
All locations (n = 2,100)
intercept	0.0163 (0.0146, 0.018)	0.0009	<0.0001
true value for β1	0.9205 (0.9125, 0.9286)	0.0041	<0.0001
Location’s distance to geographical center < 2 (n = 1,680)
intercept	0.0117 (0.0098, 0.0135)	0.0009	<0.0001
true value for β1	0.9443 (0.9356, 0.953)	0.0045	<0.0001
Location’s distance to geographical center < 1.5 (n = 924)
intercept	0.0018 (−0.0004, 0.0041)	0.0011	0.106
true value for β1	0.9947 (0.984, 1.0055)	0.0055	<0.0001