Table 1. A multivariate regression of hospitalization rate at the zip-code level with the proportion of the ZIP Code living below the poverty line and the proportion of the ZIP Code over 65.

	Estimate	Std. Error	t value	Pr(>|t|)
(Intercept)	0.3656	0.0978	3.74	0.0002
Proportion over 65	-0.0001	0.0094	-0.01	0.9911
Proportion in poverty	-0.0096	0.0043	-2.25	0.0258
Interaction	0.0022	0.0003	6.26	0.0000