Table 1.

Weighted descriptive statistics

	Full Sibling Sample	Children With No LBW Sibling	Children With 1 LBW Sibling
Parental Time Investments
Total maternal time (hrs./week)	46.12 (19.05)	45.99 (19.10)	47.31 (19.00)
Developmental time (hrs./week)	12.49 (10.34)	12.32 (10.20)	13.28 (11.33)
Child Endowment
Birth weight	119.9 (20.81)	123.27 (17.36)	93.30 (24.13)
Family Characteristics
Mother's education (yrs)	12.85 (3.07)	12.85 (3.12)	12.83 (2.60)
Prop. with high school or less	0.40 (0.49)	0.41 (0.49)	0.34 (0.48)
Log family income	10.24 (10.11)	10.25 (1.13)	10.10 (1.00)
Mother's age at child's birth	27.67 (5.34)	27.70 (5.36)	27.40 (5.80)
Prop. mothers working	0.72 (0.45)	0.79 (0.40)	0.71 (0.45)
Hrs. worked among working mothers	34.74 (13.73)	34.63 (12.69)	34.46 (15.94)
Sibship size	2.75 (0.99)	2.79 (1.02)	2.45* (0.64)
Child's age in 1997	5.96 (5.95)	6.05 (3.38)	4.91* (3.12)
School age (= 1)	0.54 (0.50)	0.55 (0.50)	0.41* (0.50)
Male (= 1)	0.50 (0.50)	0.51 (0.50)	0.51 (0.50)
Black (= 1)	0.13 (0.34)	0.12 (0.32)	0.262** (0.44)
Latino (= 1)	0.13 (0.33)	0.13 (0.33)	0.16* (0.34)
Other (= 1)	0.07 (0.07)	0.07 (0.25)	0.11 (0.37)
N	1,516	1,314	132

Notes: t test compares mean differences between children with only normal-birth-weight siblings and children with a low-birth-weight sibling. Sampling weights were used to make statistics nationally representative.

^*p < .05

^**p < .001