Table 1: Summary statistics and years of data pertaining to the 1816 blockgroups in Philadelphia County.

Mean (SD)Median (IQR 25%, 75%)

All assaults (2002–2006)5.28 (4.97)4
Gun assaults (2002–2006)1.77 (2.25)1
Nongun assaults (2002–2006)3.51 (3.50)3
No. of vacant properties (2002–2006)12.53 (16.67)6
Total population (2004)792.45 (507.09)711.5
Median age (2004)34.85 (8.35)35
Male : female ratio (2004)0.89 (0.52)0.9
No. of black residents (2004)353.22 (353.42)248
No. of Hispanic residents (2004)69.18 (136.70)20
Median household income (2004) 35297 (20046)33213
No. of unemployed (2004)42.18 (40.65)31
No. of with bachelor’s degree (2004)78.88 (105.31)43.84
No. of single parent households (2004)90.94 (60.56)83
No. of residential properties (2004)253.40 (158.70)238

*SD: standard deviation; IQR: interquartile range.