Table 2. Comparison of the mean of IQ in different variables.

Variable	IQ	P-value	t (or F)-value
Sex		0.927	−0.092
Boys	99.44±9.38
Girls	99.49±9.85
Household income		<0.001	22.468
Low	97.25±9.42
Moderate	100.00±9.37
High	102.03±9.61
Place of residence		<0.001	24.988
Metropolitan	103.50±10.34
Urban	100.92±8.96
Suburban	99.68±9.29
Rural	95.98±9.29
Subrural	95.47±7.32
Previous education		<0.001	6.577
Positive	100.19±9.59
Negative	94.89±8.37
Delivery type		<0.001	6.745
C/S	101.27 ±9.56
NVD	97.57 ±9.28
Infant feeding		<0.001	3.796
Breast feeding	100.67 ±10.01
Formula	98.52±9.17
Father's education		<0.001	87.096
Low	96.65±9.03
Moderate	99.93±8.57
High	110.73±11.31
Mother's education		<0.001	65.540
Low	96.71±9.05
Moderate	100.88±9.08
High	114.92±10.76

Abbbreviations: C/S, cesarean section; IQ, intelligent quotient; NVD, normal vaginal delivery.