Dear SPMers,
A few days ago, I posted a question about contrasts, but I could not
receive any answer. I'm sorry for reposting this.
If I have 3 conditions including two experimental (let's say A and B)
and a control conditions, the t-maps for all conditions would be
calculated by using simple t-test at the individual analysis. And
then, I can specify "A>control" and "B>control" at the group level.
But, in different way, I can make "A>control" and "B>control" using
two-sample t-test at the individual level then I can run simple t-test
for "A>B" or "B>A" as well as "A>control" and "B>control".
In other words, at the following table,
the first way the second way
1st level A, B & control (simple t-test) [A>control] & [B>control]
2nd level A>control & B>control [(A>control)>0],
[(B>control)>0], [A>B] & [B>A]
[A>control] in the first way and [(A>control)>0] are same?
Otherwise, which way is a better way?
I appreciate your help in advance.
--
Chobok Kim
e-mail: [log in to unmask]
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