TABLE 2—

Summary Statistics for Variables From the 2000 US Census

	Zip Code Sample
Population, mean (SD)	10 006.27 (13 423.91)
Race, %a
White	75.07
Black	12.23
Asian American	3.62
Other	9.08
Hispanic, %a	12.54
Median household income,a $10 000s (SD)	4.4833 (1.7119)
Urbanization category, %
Urban	29.92
Suburban	9.71
Rural	56.07
Farm	4.30
Region, %
Northeast	18.25
Midwest	30.67
South	35.22
West	15.85
No. of zip codes	28 050

^aPopulation-weighted.