I performed a one condition across two groups (G1, G2) contrast with a covariate in 3dMEMA. Using 3dinfo, I found that the t-stats for one of the groups (G2) are absent (please see 3dinfo output below at sub-brick #3) but that the t-stats for the other group and for the contrast between groups are present. When I run this analysis with a different mask or with different sub-bricks from the same Rbucket file, this problem does not consistently appear. I would appreciate any help in determining what happened to the t-stats for one group. Please response to Betty Jo Salmeron (email above) or Tom Ross regarding this question as I am in my last few days as a NIDA post-bac. Thank you!

Dataset File: TaskEvent_Thinkvs0_G2-G1_covAge+tlrc
Identifier Code: XYZ_w27UfuasIu1WZBvtDjY1nA Creation Date: Wed Jun 20 16:32:36 2012
Template Space: ORIG
Dataset Type: Func-Bucket (-fbuc)
Byte Order: MSB_FIRST [this CPU native = LSB_FIRST]
Storage Mode: BRIK
Storage Space: 5,432,660 (5.4 million) bytes
Geometry String: "MATRIX(-3,0,0,90,0,-3,0,126,0,0,3,-72):61,73,61"
Data Axes Tilt: Plumb
Data Axes Orientation:
first (x) = Left-to-Right
second (y) = Posterior-to-Anterior
third (z) = Inferior-to-Superior [-orient LPI]
R-to-L extent: -90.000 [R] to 90.000 [L] step 3.000 mm [ 61 voxels]
A-to-P extent: -90.000 [A] to 126.000 [P] step 3.000 mm [ 73 voxels]
I-to-S extent: -72.000 [I to 108.000 [S step 3.000 mm [ 61 voxels]
Number of values stored at each pixel = 10

At sub-brick #0 'G1_Thinkvs0:b' datum type is short: -22233.2 to 32767 [internal]
[* 2.92559e-05] -0.650452 to 0.958627 [scaled]
At sub-brick #1 'G1_Thinkvs0:t' datum type is short: -13975.8 to 32767 [internal]
[* 0.000398152] -5.56448 to 13.0462 [scaled]
statcode = fitt; statpar = 30
At sub-brick #2 'G2_Thinkvs0:b' datum type is short: -21758.4 to 32767 [internal]
[* 2.7977e-05] -0.608734 to 0.916722 [scaled]
At sub-brick #3 'G2_Thinkvs0:t' datum type is short: 0 to 0
statcode = fitt; statpar = 30
At sub-brick #4 'PG2_Thinkvs0-G1_Thinkvs0:b' datum type is short: -32767 to 25826.6 [internal]
[* 2.46559e-05] -0.807899 to 0.636777 [scaled]
At sub-brick #5 'G2_Thinkvs0-G1_Thinkvs0:t' datum type is short: -32767 to 30404.7 [internal]
[* 0.000198628] -6.50845 to 6.03923 [scaled]
statcode = fitt; statpar = 30
At sub-brick #6 'Age:b' datum type is short: -29498.8 to 32767 [internal]
[* 9.68835e-07] -0.0285794 to 0.0317458 [scaled]
At sub-brick #7 'Age:t' datum type is short: -31467.4 to 32767 [internal]
[* 0.000183942] -5.78816 to 6.02721 [scaled]
statcode = fitt; statpar = 30
At sub-brick #8 'tau^2' datum type is short: 0 to 32767 [internal]
[* 4.30448e-05] 0 to 1.41045 [scaled]
At sub-brick #9 'QE:Chisq' datum type is short: 0 to 32767 [internal]
[* 0.00305185] 0 to 100 [scaled]
statcode = fict; statpar = 30