Variable | Selected (N = 600) | Not Selected (N = 1420) | |||||
---|---|---|---|---|---|---|---|
 | N | Mean | Std | N | Mean | Std | p-value |
Birth weight (g) | 600 | 3387.8 | 493.3 | 1420 | 3353.7 | 533.0 | 0.92 |
Gestation (days; LMP to term) | 600 | 282.1 | 12.7 | 1404 | 279.1 | 16.3 | <.001 |
Number of Previous Live Births | 600 | 1.7 | 1.7 | 1420 | 1.9 | 1.8 | 0.09 |
 | N | % |  | N | % |  | p-value |
Male | 300 | 50.0 | Â | 703 | 49.5 | Â | 0.84 |
Mother Education at Child’s Birth |  |  |  |  |  |  |  |
 < High School | 74 | 12.3 |  | 169 | 11.9 |  | 0.58 |
 High School Graduate | 202 | 33.7 |  | 477 | 33.6 |  |  |
 Some College/Trade School | 200 | 33.3 |  | 444 | 31.3 |  |  |
 College Graduate or Higher | 123 | 20.5 |  | 329 | 23.2 |  |  |
 Missing | 1 | 0.2 |  | 1 | 0.1 |  |  |
Maternal Smoking During Pregnancy | Â | Â | Â | Â | Â | Â | Â |
 Never Smoked | 315 | 52.5 |  | 662 | 46.6 |  | 0.16 |
 Smokes Now | 180 | 30.0 |  | 490 | 34.5 |  |  |
 Smoked Until Current Pregnancy | 40 | 6.7 |  | 119 | 8.4 |  |  |
 Former Smoker | 61 | 10.2 |  | 136 | 9.6 |  |  |
 Missing | 4 | 0.7 |  | 13 | 0.9 |  |  |