Dear SPM experts,
We are perfoming a longitudinal analysis, with two groups (experimental and control) and two times (pre-treatment and post-treatment). We have 27 subjects. For ANOVA 2x2 analysis, we have used these contrasts:
F-test interaction: 0 0 0 0 + (27 zeros) + 1 -1 -1 1 --> correctly performed
T test group main effect: 1 -1 0 0 + (27 zeros) + 0.5 0.5 -0.5 -0.5 --> error "invalid contrast"
T test time main effect: 0 0 1 -1 + (27 zeros) + -0.5 0.5 -0.5 0.5 --> error "invalid contrast"
Is there something wrong in the contrast?
Could you help us?
Thank you in advance,
Maria.
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