Table 1.

Means (Standard Deviations, and 95% Confidence Intervals) by Sex for Laboratory-and Parent-assessed Anger and IC

	Males	Females	Effect Size
Laboratory Ratings
Anger 12 months	.05 (.95, −.04–.14)	−.05 (1.05, −.15–.05)	.10
Anger 36 months	.19 (1.01, .10–.28)	−.18 (.95, −.27– −.10)	.38*
IC 36 months	−.27 (1.06, −.36–−.18)	.26 (.87, .18–.33)	−.55*
Parent Ratings
Anger 12 months	.06 (1.0, −.04–.16)	−.07 (1.0, −.17–.03)	.13
Anger 36 months	.06 (.96, −.04–.16)	−.06 (1.04, −.17–.05)	.12
IC 36 months	−.19 (1.01, −.29–−.09)	.21 (.95, .11–.31)	−.41*

Note.

^*corresponding z-statistics were significant for these variables, indicating a significant sex difference.

Effect sizes estimated as Cohen’s d express group differences in standard deviation units. N=735 children assessed by parent ratings; N=846 assessed for anger in the laboratory at 12 months; N=1000 assessed for anger in the laboratory at 36 months; and N=1021 children assessed for IC in the laboratory at 36 months.