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. Author manuscript; available in PMC: 2013 Mar 1.
Published in final edited form as: Neuroimage. 2011 Dec 30;60(1):747–765. doi: 10.1016/j.neuroimage.2011.12.060
Test Student t-test MEMA
Gaussian Laplacian
Results TS TKH TS TKH
Voxel 1 Group effect Estimate 0.643 0.667 0.682
t 4.542 5.006 5.153 5.942 5.443
pa 0.0014 7.33e – 4 6.01e – 4 2.17e – 4 4.09e – 4
Cross-subjects heterogeneity 2b 0.200 0.0633 0.0296
Qc 15.11 (0.0880)
H, I2d 1.296, 0.406 1.149, 0.242
Voxel 2 Group effect Estimate 0.508 0.381 0.364
t 3.89 5.536 4.705 7.334 5.156
pa 3.67e – 3 3.63e – 4 1.11e – 3 4.40e – 5 5.98e – 4
Cross-subjects heterogeneity 2b 0.171 0.0177 0.0004
Qc 18.49 (0.0299)
H, I2d 1.30, 0.409 1.009, 0.018
Voxel 3 Group effect Estimate − 0.319 −0.319 −0.323
t − 3.168 − 5.020 − 4.501 − 4.564 − 4.308
pa 0.011 7.20e – 4 1.49e – 3 1.36e – 3 1.97e – 3
Cross-subjects heterogeneity 2b 0.101 0 0.007
Qc 11.20(0.2622)
H, I2d 1.0, 0.0001 1.081, 0.145
Voxel 4 Group effect Estimate − 0.193 − 0.138 − 0.138
t − 5.449 − 2.971 − 3.915 − 2.971 − 3.915
pa 4.1e – 4 1.57e – 2 3.54e – 3 1.57e – 2 3.54e – 3
Cross-subjects heterogeneity 2b 0.0013 0 0
Qc 5.18 (0.8183)
H, I2d 1.0, 0.0 1.0, 0.0
Voxel 5 Group effect Estimate 0.0496 0.0493 0.0493
t 4.7152 0.8937 4.6376 0.8937 4.6376
pa 0.0011 0.3947 0.0012 0.3947 0.0012
Cross-subjects heterogeneity 2b 1.1e-4 0 0
Qc 0.3342 (1.0)
H, I2d 1.0, 0.0 1.0, 0.0

Talairach coordinates (x, y, z) of the five voxels: (31, −91, −2) (Voxel 1), (−23, −89, 0) (Voxel 2), (−53, −17, 10) (Voxel 3), (−51, −11, 6) (Voxel 4), and (−5, 11, 0) (Voxel 5), where + x, y, z=RAS (neurological coordinates)

a

p-values for the t-statistics with 9 degrees of freedom are two-sided.

b

The variance for the conventional approach (paired Student t-test) is the estimated τ2+σ2 in the effect estimates, including both within- and inter-subject variances, assuming the within-subject variability being homogeneous in the group. The adjustment in TKH relative to TS does not involve the estimate of inter-subject variability τ2, which remains the same between the two tests.

c

The conventional approach assumes equal or no within-subject variance; thus, all the variability in the data is assumed to come between subjects. There is no way to test the significance of the inter-subject variability in the case of paired Student t-test under this assumption. The Q-statistic, defined in (8) for testing inter-subject variability (null hypothesis τ2=0), follows a χ2(9) distribution with the data at the five voxels (p-value shown within parentheses).

d

Approximate criteria for heterogeneity: H>1.5 (or I2>0.56), significant; 1.2<H<1.5 (or 0.31<I2<0.56), moderate; H<1.2 (or I2<0.31), negligible.