Table 1.

Levene test statistics and degrees of freedom (W_{(df1, df2)}) displaying the significant and nonsignificant differences in group-level variance in the in vivo GABA+/Cr measurements derived from 16, 40, 64, 96, 140 or 200 signal averages compared to the full dataset (the data containing 300 averages) for each of the five voxels. Note that df2 differs across the voxels as some datasets were removed from further analysis following data quality control.

N_avg (vs. 300)	Voxel

	AUD	DLPFC	FEF	OCC	SM
16	4.63_{(1, 28)}^*	4.54_{(1, 32)}^*	4.48_{(1, 32)}^*	4.44_{(1, 30)}^*	1.54_{(1, 32)}
40	4.50_{(1, 28)}^*	18.00_{(1, 32)}^***	9.56_{(1, 32)}^**	6.80_{(1, 30)}^*	2.82_{(1, 32)}
64	4.65_{(1, 28)}^*	4.15_{(1, 32)}^*	5.47_{(1, 32)}^*	3.52_{(1, 30)}	1.30_{(1, 32)}
96	6.52_{(1, 28)}^*	5.25_{(1, 32)}^*	5.61_{(1, 32)}^*	1.48_{(1, 30)}	0.49_{(1, 32)}
140	6.27_{(1, 28)}^*	2.01_{(1, 32)}	2.88_{(1, 32)}	0.68_{(1, 30)}	0.20_{(1, 32)}
200	0.15_{(1, 28)}	0.25_{(1, 32)}	1.03_{(1, 32)}	0.44_{(1, 30)}	0.37_{(1, 32)}

^***

p < 0.001,

^**

p < 0.01,

p < 0.05.