I am conducting a two-stage random effects analysis for a block-design study
comparing 2 subject populations using SPM2. At the first level, I am
specifying a t contrast for each subject, experimental condition minus
control condition by entering "1 -1" (con1). I am also specifying a t
contrast for the control minus the experimental condition by entering "-1 1"
(con2)...which essentially amounts to a two-tailed t-test...I think. Then,
at the second level I am taking each of these contrasts and comparing
population 1 to population 2 using a two-sample t-test by entering "1 -1"
and "-1 1." However, my results look the same for the con1, pop1 vs. pop2
comparison and the con2, pop2 vs. pop1 comparison. What am I missing?
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