Table 2.

Effects of Attentional and Motor Impulsivity, Sex, and their Interaction on Age at First Methamphetamine Use

A) Attentional Impulsivity
Coefficientsa
Model		Unstandardized Coefficients		Standardized Coefficients	t	Sig.	95.0% Confidence Interval for B		Correlations
		B	Std. Error	Beta			Lower Bound	Upper Bound	Zero- order	Partial	Part
1	(Constant)	22.682	.550		41.246	.000	21.595	23.768
	Centered_YearsMAUse	−.394	.064	−.442	−6.129	.000	−.521	−.267	−.442	−.442	−.442
2	(Constant)	22.717	.638		35.614	.000	21.457	23.977
	Centered_YearsMAUse	−.348	.065	−.390	−5.349	.000	−.476	−.219	−.442	−.398	−.378
	Sex	−.164	1.230	−.010	−.134	.894	−2.594	2.265	−.071	−.011	−.009
	Centered_BIS_Attention	−.371	.138	−.226	−2.685	.008	−.645	−.098	−.311	−.213	−.190
	Centered_BIS_Attention_Sex	.037	.275	.011	.134	.893	−.506	.580	−.126	.011	.009

B) Motor Impulsivity
Coefficientsa
Model		Unstandardized Coefficients		Standardized Coefficients	t	Sig.	95.0% Confidence Interval for B		Correlations
		B	Std. Error	Beta			Lower Bound	Upper Bound	Zero-order	Partial	Part
1	(Constant)	22.682	.550		41.246	.000	21.595	23.768
	Centered_YearsMAUse	−.394	.064	−.442	−6.129	.000	−.521	−.267	−.442	−.442	−.442
2	(Constant)	22.767	.633		35.955	.000	21.516	24.018
	Centered_YearsMAUse	−.350	.065	−.393	−5.429	.000	−.478	−.223	−.442	−.403	−.381
	Sex	−.419	1.204	−.025	−.348	.728	−2.799	1.960	−.071	−.028	−.024
	Centered_BIS_Motor	−.372	.122	−.267	−3.056	.003	−.613	−.132	−.298	−.241	−.215
	Centered_BIS_Motor_Sex	.166	.215	.067	.773	.441	−.258	.590	−.077	.063	.054

^aDependent Variable: Age of first meth use