Built and socioeconomic environments: patterning and associations with physical activity in U.S. adolescents

Table 2 Built and socioeconomic environment characteristics: descriptive statistics¹

Measure	mean (SE)	min	25th	median	75th	max
Street connectivity
Alpha index	0.32 (0.01)	-8	0.22	0.30	0.38	8
Intersection density	29.5 (1.65)	0	8.6	26.4	44.6	168.1
Population density	1,410 (182)	0.05	128	794	1,779	29,961
Landscape diversity
Mean patch size	30,196 (1,566)	7,411	14,213	88,250	32	315,000
Patch size variability	171,517 (6,853)	21,151	19,147	131,745	52	939,810
Land patch density	52.4 (1.7)	3.2	32.5	52.2	70.4	134.9
Simpson's diversity index	0.54 (0.01)	0.01	0.45	0.58	0.67	0.83
Contagion index	48.3 (0.9)	9.1	36.2	45.8	57.9	98.3
Perimeter-fractal dimension	1.48 (0.01)	1.06	1.44	1.50	1.54	1.67
Physical activity facilities
Instruction	2.3 (0.2)	0	0	1	3	100
Member	2.0 (0.2)	0	0	1	3	52
Outdoor	1.2 (0.1)	0	0	1	2	15
Public	0.9 (0.1)	0	0	0	1	22
Public fee	1.4 (0.1)	0	0	1	2	22
Youth organization	1.3 (0.2)	0	0	0	2	38
Parks	4.7 (0.5)	0	0	1	8	44
Census measures
% below poverty	0.15 (0.01)	0	0.06	0.11	0.21	0.85
% ≥ college education	0.23 (0.01)	0.01	0.13	0.19	0.29	0.82
% minority	0.21 (0.02)	0	0.02	0.08	0.29	1
Median household income	29,753 (935)	4,999	21,003	28,462	35,643	125,053
% homeowners	0.68 (0.01)	0	0.56	0.72	0.83	0.98
Crime rate	5,476 (237)	108	3,523	5,528	6,975	13,723

¹ National Longitudinal Study of Adolescent Health, Wave I (1995-96), n = 18,294. Excludes built environment characteristics examined but not included in subsequent analysis

ISSN: 1479-5868