Table 1.

Demographic Characteristics of Groups

	Randomized Group				Functional Grouping
					Some	Always
Group	A	B	C	P	<7 books	7 or more	P
Number	16	18	18		18	34
A					9	7
B					6	12
C					3	15	0.007
Gender (female)^{^a}	62.50%	27.78%	50.00%	0.118	44.44%	47.06%	0.857
GA^{^b}	38.5	38.6	39.3	0.354	38.4	38.9	0.657
Delivery (cesarean)^{^a}	37.50%	44.44%	38.89%	0.807	50.00%	35.29%	0.466
NICU^{^a}	18.75%	16.67%	11.11%	0.894	16.67%	14.71%	0.852
Maternal age^{^b}	29.6	25.6	27.5	0.053	28.3	27.1	0.308
Paternal age^{^b}	32.2	28.2	29.8	0.181	31.4	29.2	0.305
Maternal education level^{^b}	13.4	13.7	15.2	0.035	12.6	14.9	0.015
Paternal education level^{^b}	12.6	13.7	13.8	0.709	12.1	14.1	0.034
Birth order^{^b}	2.5	1.9	1.9	0.341	2.4	1.9	0.302
Number of adults^{^b}	2.6	2.3	2.2	0.629	2.7	2.2	0.149
Number of kids^{^b}	2.4	1.8	2.1	0.508	2.5	1.9	0.141

Abbreviations: A, books only; B, books and commitment to read 1 book a day; C, books and commitment to read 1 book a day and video; NICU, the neonatal intensive care unit.
↵a Fischer's exact test.
↵b Kruskal-Wallis test.