. Author manuscript; available in PMC: 2012 Jul 1.

Published in final edited form as: J Hum Cap. 2011 Summer;5(2):207–254. doi: 10.1086/660885

Table 4.

Effects of Smoking Participation and Number of Cigarettes during Pregnancy on the Probability of High Neurodevelopment Risk Status^a

Model	Total Sample	Low Socioeconomic Status	High Socioeconomics status
	Smoking participation
Probit	0.072^** (0.031)	0.075^* (0.042)	0.089 (0.062)
Bivariate Probit	0.401^** (0.180)	0.544^*** (0.140)	0.283 (0.533)
F-statistic	10.3^*** [2, 23]	7.33^** [2, 22]	6.19^*** [2, 23]
Over-identification Chi-square [1]	1.51	1.45	1.89
Exogeneity Chi-square [1]	3.4^*	5.63^**	0.16

	Cigarettes
Probit	0.006^* (0.003)	0.007^* (0.004)	0.007 (0.006)
IV Probit	0.032 (0.028)	0.035 (0.029)	-
F-statistic [df]	42.1^*** [2,23]	23.96^*** [2, 22]	-
Over-identification Chi-square [1]	0.09	0.19	-
Exogeneity Chi-square [1]	1.04	1.24

Note: Standard errors of effects are in parentheses.

^{*, ** and ***}

indicate p <0.1, <0.05 and <0.01, respectively.