Hi Anderon,
Thank you for your reply.
Please let me make sure that you meant that I should process one-sample t test using 4D FA skeleton of L-R without any covariates as one way?
Best regards,
Akira Yogi
On Wed, 5 Aug 2015 07:51:32 +0100, Anderson M. Winkler <[log in to unmask]> wrote:
>Hi Akira,
>
>The first contrast (C1) is fine for testing laterality: if there is no
>effect, the average is zero. However, the same contrast, if applied to the
>original FA maps (i.e., not L-R differences), isn't informative and can be
>problematic. This contrast tests then if FA is larger than zero, but we
>know that this is true without any test. Trying to test it causes the
>statistic to reach extremely high values, which give the warnings when
>computing TFCE
>
>So, either use C1 to test laterality, or drop it if the idea is to test FA
>itself.
>
>All the best,
>
>Anderson
>
>
>
>--
>Anderson M. Winkler
>FMRIB / Analysis Group
>[ Blog <http://brainder.org/> | Twitter <http://twitter.com/AndersonWinkler>
> ]
>
>
>On 4 August 2015 at 17:24, Akira Yogi <[log in to unmask]> wrote:
>
>> Hi Anderson,
>>
>> I put the original values without rounding off. Since I could not paste
>> the copied data, I entered them manually.
>> Anyway, I restarted randomization on a same computer but it does not work
>> after showing the warning: "tfce has detected a large number of integral
>> steps. This operation may require a great deal of time to complete".
>> Even though 14 hours later, the calculation have not progressed at all.
>> Is it because I put the complicated values (with the order of 10^-16)?
>>
>> Here I attached the matrices just in case.
>>
>>
>> Best regards,
>> Akira Yogi
>>
>>
>>
>>
>> On Tue, 4 Aug 2015 07:44:37 +0100, Anderson M. Winkler <
>> [log in to unmask]> wrote:
>>
>> >Hi Akira,
>> >
>> >Excel can give values very close to zero (something to the order of 10^-16
>> >I think). Check the formatting options as these other decimal places may
>> be
>> >hidden. Also, use copy/paste to put the files in the Glm_gui window, so
>> >that these are preserved.
>> >
>> >All the best,
>> >
>> >Anderson
>> >
>> >
>> >
>> >On 4 August 2015 at 00:58, Akira Yogi <[log in to unmask]> wrote:
>> >
>> >> Hi Anderson,
>> >>
>> >> Thank you for your reply.
>> >> As you told, the covariate values were rounded off to two decimal places
>> >> by Excel's function, resulting in incomplete zero mean.
>> >> I will try to put the value particularly as possible as Excel can show,
>> >> but it seems to be impossible to have these values being completely
>> >> zero-mean.
>> >>
>> >>
>> >> Akira Yogi
>> >>
>> >
>>
>
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