Hi,
have you looked at p<0.1 instead of 0.05 for the (two tailed) F-test, does
that match better with your t-tests?
Cheers,
Andreas
Am 07.10.11 06:39 schrieb "Chou Kun Hsien" unter <[log in to unmask]>:
>Sorry that i didn't clarify my question.
>the following is the original question asked by Dr. John Colby
>
>>What I am confused about is this: When age is included as a covariate (as
>>opposed to when it is not), the individual FA_tfce_corrp_tstat maps are
>>more
>>robust, but the overall F-test map (FA_tfce_corrp_fstat) drops almost to
>>zero. This opposite behavior surprised me and makes me think that I
>>might be
>>doing something wrong in my model setup, or perhaps just not fully
>>understanding how F-tests work in FSL. Does this seem like normal
>>behavior,
>>or does it look like I'm doing something wrong?
>
>we also met the same question like above.
>the f-test result seems a lil bit different with the t-test result from
>each t-contrast.
>the f-values were small, and we can barely detect any significant
>difference from f-test in TFCE (while p<0.05).
>i think it is not a normal result.
>cuz the f-test findings should not be so different from t-test, since we
>got many significant findings from t-test analysis.
>there must be something wrong with my F-test setting, or i must
>misunderstanding the meaning of F-test in FSL...
>Any help would be so appreciated!!!
>
>thanks
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