Table 1.

Demographic data for the full sample included in this study.

	n	Mean	SD	Minimum	Maximum
Infant age in days (6 m)	45	182.02	5.43	174	196
Infant age in days (9 m)	42	274.6	6.49	266	295
Mother’s age in years	42	34.86	5.71	21	47
Mother’s years of education	41	17.8	2.74	13	26
Father’s age in years	41	35.56	6.05	23	52
Father’s years of education	39	17.0	2.18	11	21