Table 2.

Summary effect sizes within each age group.

Age group (mean age)	k	N	Weighted Effect Size			95% CI for M*		mean weighted correlation (r)	Homogeneity Tests
			mean (M*)	se	p				Qw	df	p
Overall	31	2806	0.153	0.039	<.001	0.077	0.230	0.152	118.03	30	<.001
20–29	9	518	0.060	0.088	0.495	−0.112	0.232	0.060	28.31	8	<.001
30–39	4	312	0.082	0.079	0.301	−0.073	0.237	0.082	3.68	3	0.299
40–50	8	920	0.314	0.070	<.001	0.178	0.450	0.304	31.04	7	<.001
50–59	2	170	0.106	0.124	0.393	−0.137	0.350	0.106	2.45	1	0.117
60–69	4	709	0.173	0.056	0.002	0.063	0.282	0.171	5.82	3	0.121
70–79	3	147	0.107	0.082	0.190	−0.053	0.267	0.107	1.43	2	0.489
>80	1	30	−0.249	0.174	0.153	−0.590	0.093	−0.244	--	--	--

Note: Positive effect sizes refer to the relationship that larger prefrontal volume is associated with better executive function. k = number of effect sizes included in the analysis; N = cumulative sample size across studies; se = standard error of weighted mean; CI = confidence interval.