Table 3.

Regression models using age and prefrontal laterality to predict fluid ability.

Model	Regressors	Single regressor statistics
		b values	t scores	p values
Categorical Age	Intercept	0.22	3.15	.002
	Sex	0.21	3.34	.001
	Crystallized Ability	0.40	12.43	< 0.001
	Age (young - middle)	0.80	8.39	< 0.001
	Age (old - middle)	−1.00	−13.66	< 0.001
	Age (old - young)	−1.80	−20.62	< 0.001
	Laterality	0.18	2.98	.003
	Age × Laterality (young - middle)	−0.07	−0.76	.446
	Age × Laterality (old - middle)	−0.30	−4.00	< 0.001
	Age × Laterality (old - young)	−0.22	−2.62	0.009
Continuous Age	Intercept	−0.10	−1.88	.061
	Sex	0.21	3.60	< 0.001
	Crystallized Ability	0.39	13.47	< 0.001
	Agelinear	−0.93	−14.05	< 0.001
	Agequadratic	−0.01	−0.31	756
	Agecubic	0.07	2.37	.018
	Laterality	0.02	0.40	.688
	Agelinear × Laterality	−0.15	−2.25	.025
	Agequadratic × Laterality	−0.003	−0.08	.937
	Agecubic × Laterality	0.03	0.87	.386

Note. All regressors except age group and sex were entered as standardized variables and have b-values that are standardized β-values. Laterality was measured in the combined ventrolateral/dorsolateral prefrontal mask. Terms comparing old vs. young estimated from separate models.