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. Author manuscript; available in PMC: 2014 Dec 24.

Published in final edited form as: Infant Behav Dev. 1998;21(4):627–640. doi: 10.1016/S0163-6383(98)90034-0

Table 3.

Group differences on Bayley scales of infant development

	Exposed (N = 74) M (SD)	Unexposed (N = 93) M (SD)	t or F Test
Test age (months)	11.9 (0.6)	12.1 (0.5)	t(1, 165) = 2.5^*
MDI^a	103.8 (1.6)	107.9 (1.5)	F(1, 158) = 3.2^#
PDI^a	100.6 (1.7)	105.0 (1.5)	F(1, 158) = 3.5^#
IBR Factor^a
General	3.4 (0.4)	2.3 (0.3)	F(15, 133) = 2.6^**
Test affect	1.2 (0.2)	0.9 (0.2)	F(6, 142) = 2.3^*
Activity	0.6 (0.1)	0.2 (0.1)	F(3, 146) = 3.5^*
Orientation	1.5 (0.2)	1.1 (0.1)	F(4, 145) = 2.2^#
Audio-Visual	1.5 (0.1)	1.1 (0.1)	F(3, 145) = 3.6^*
Motor	0.5 (0.1)	0.4 (0.1)	F(2, 147) = 2.7^*

MDI = Mental Development Index;

PDI = Psychomotor Development Index;

IBR = Infant Behavior Record;

^a

Gestational Age Covaried;

^**

p < .01;

^*

p < .05;

^#

p< .10.