Table 3. Bivariate Results^a for Density of and Distance to Food Outlets between Tribal Areas^b and Non-Tribal Areas^c.

Mean	Healthy Outlet Composite	Supermarkets, Superstores, & Produce Markets	Healthy Specialty Stores	Intermediate Outlet Composite	Mixed Specialty Stores	Sit-down Restaurants	Unhealthy OutletComposite	Fast Food	Carryout & Unhealthy Specialty Stores	Convenience Stores & Gas Stations
N	15,303	12,037	3,280	47,419	1,604	46,015	44,609	16,812	18,488	9,415
Density d
Census Tracts with Tribal Land	0.0020	0.0014	0.00037	0.0031	0.000098	0.0030	0.0035	0.0011	0.0011	0.00078
Census Tracts without Tribal Lands	0.26	0.20	0.036	1.2	0.018	1.1	1.3	0.44	0.44	0.21
Difference e	0.26	0.20	0.036	1.2	0.018	1.1	1.3	0.44	0.44	0.21
p value	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Distance f
Tribal Census Tracts	6.0	6.0	20	6.3	28	6.4	8.5	12	11	11
Census Tracts without Tribal Lands	1.7	1.8	3.4	1.6	5.5	1.6	1.7	2.1	2.1	2.0
Differencee	-4.2	-4.2	-17	-4.7	-22	-4.8	-6.8	-9.9	-8.7	-8.5
p value	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001

^a T-test with unequal variance. All numbers were rounded to two significant digits.

^b In the distance analyses, tribal areas refer to “tribal census tracts” as defined by the US Census (n = 94) including primarily the land area of federally recognized American Indian reservations or off-reservation tribal lands. In the density analyses, tribal areas refer to census tracts that contain tribal lands (n = 52)

^c Non-tribal areas refer to census tracts without tribal lands (n = 2284 for distance, n = 2300 for density) in counties with tribal lands

^d Density of food outlets per square mile was obtained for each census tract using the kernel density estimation

^e difference = nontribal–tribal; differences are the same as the census tract without tribal lands due to rounding.

^f Distance is calculated as the shortest distance along the road network from the tribal census tract centroid to the closest food outlet of the respective category.