Dear all,
I am getting confused with results from different tests. If my
understanding is correct, there should be no difference if I:
(1) contrast A > B in 1st level and make one-sample t-test in 2nd level OR
(2) contrast A and B separately in 1st level (contrast "1") and bring
them to full-factorial (ANOVA) or two-sampled t-test.
Well, this is not the case. Two-sample and full-factorial are
producing different results (even when I set dependent measurements). With
one-sample t-tests I find strong activity (FWE corrected), which
disappears if I follow way 2. Only the paired t-test produces the same identical
result as the one-sample t-test.
Can someone explain the differences between these tests?
Does this suggest it's better to do many one-sample t-tests instead
of a single ANOVA in 2nd level?
Do ANOVA really loose statistical power (maybe because of degrees of freedom)?
Any help is welcome. Thanks in advance.
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