TABLE 4.

Hierarchical Regressions for Predictors of Motivation to Change Marijuana Use (N = 125)^a

Step	R	$R_{\mathrm{Adj}}^2$	Δ R2	Anova
	MEEQ-Bp
1) Age first used	0.240	0.050	0.058	F (1, 123) = 7.53, p < .007
2) No. days smoked in last 3 mo.	0.272	0.059	0.016	F(2,122) = 4.86, p < .009 FCH(1, 122) = 2.12, p > .148
3) MEEQ-Bp	0.288	0.060	0.009	F(3, 121) = 3.65, p < .015 FCH(1, 121) = 1.20, p > .276
	MEEQ-Bn
1) Age first used	0.240	0.050	0.058	F(1, 123) = 7.53, p < .007
2) No. days smoked in last 3 mo.	0.272	0.059	0.016	F(2,122) = 4.86, p < .009 FCH(1, 122) = 2.12, p > .148
3) MEEQ-Bn	0.462	0.194	0.140	F(3, 121) = 10.94, p < .001 FCH(1, 121) = 21.46, p < .001

Note. MEEQ-B_p = Marijuana Effect Expectancy Questionnaire—Adolescent Brief, positive scale; MEEQ-B_n = Marijuana Effect Expectancy Questionnaire—Adolescent Brief, negative scale.

^aN = 125 because this variable calculated only if adolescent had access to marijuana for ≥45 days out of 90.