Table 1.

Demographics by developmental status group (developmental delays, typical development)

Variable	Delayed development (n = 91)	Typical development (n = 127)	t or χ2	P
Child sex: % boys	65.9	52.0	χ2 = 3.69	ns (.055)
Child race: % Caucasian	58.2	61.4	χ2 = 0.11	ns
Child age at assessment: mean mo.	35.6	34.9	t = 1.53	ns
Bayley mental development index	60.4	104.2	t = 26.01	<.001
Mother age in years: mean	32.5	34.1	t = 2.05	.041
Mother grade completed: mean	14.3	15.8	t = 4.34	<.001
Mother employment: % employed	48.4	61.4	χ2 = 3.16	ns
Marital status: % married	80.2	89.0	χ2 = 2.58	ns
Father age in years: mean	36.3	36.6	t = 0.32	ns
Father grade completed: mean	14.0	15.8	t = 4.28	<.001
Family income: % > $50,000	41.8	58.7	χ2 = 5.43	.02