Hi Akira,
These look mostly fine. The age hasn't been completely mean-centered (that
is, it has a non-zero mean that isn't negligible). Other than that,
everything seems fine.
The nuisance absorbs some of the variance that otherwise would to into the
residuals of the GLM. Since this variance can be explained by the model,
and the residuals become smaller, it is expected that the result for C1
(average laterality) become more significant, even if age alone fails to
reach significance (there is also the multiple testing correction that
makes any relationship less clear w.r.t. significance of the variables).
I'd say as done it's fine, just please, make sure that the age column as a
zero mean.
All the best,
Anderson
On 2 August 2015 at 21:21, Yogi, Akira <[log in to unmask]> wrote:
> Hi Anderson,
>
> I am sorry for sending wrong files.
> Please see the attached.
>
>
> Best,
> Akria Yogi
>
>
>
> ------------------------------
> *差出人:* FSL - FMRIB's Software Library [[log in to unmask]] が Anderson M.
> Winkler [[log in to unmask]] の代理で送信しました
> *送信日時:* 2015年8月2日 1:31
>
> *宛先:* [log in to unmask]
> *件名:* Re: [FSL] FW: question about the interpretation of one-sample t
> test with covariate
>
> Hi Akira,
>
> These aren't design matrices I'm afraid. The files that would be helpful
> to look are the design.mat and design.con that were used as inputs to
> randomise. Thanks.
>
> All the best,
>
> Anderson
>
>
> On 31 July 2015 at 19:45, Yogi, Akira <[log in to unmask]> wrote:
>
>> Hi Anderson,
>>
>> Thank you for your suggestion.
>> Please see the attache files of matrices.
>> i am sure that all the values fed into FEAT were demeaned: I subtracted
>> the mean value from each subjects' original values.
>>
>>
>> Thanks,
>> Akira Yogi
>>
>>
>>
>> ------------------------------
>> *差出人:* FSL - FMRIB's Software Library [[log in to unmask]] が Anderson M.
>> Winkler [[log in to unmask]] の代理で送信しました
>> *送信日時:* 2015年7月31日 0:37
>> *宛先:* [log in to unmask]
>> *件名:* Re: [FSL] FW: question about the interpretation of one-sample t
>> test with covariate
>>
>> Hi Akira,
>>
>> Are you completely sure that age was mean-centered before being entered
>> in the model? Please, feel free to attach the design.mat and design.con so
>> we could have a look.
>>
>> All the best,
>>
>> Anderson
>>
>>
>> On 30 July 2015 at 17:03, Akira Yogi <[log in to unmask]> wrote:
>>
>>> Thank you for replying Anderson,
>>>
>>> I see.
>>> Let me make sure that I can get the average mean laterality (adjusted
>>> for age) and positive and negative relationship with age if I set C1 as [1,
>>> 0], C2 as [0, 1], and C3 as [0, -1].
>>>
>>> I processed FEAT as above and moved randomisation following the notes in
>>> FEATwiki. Though many tracts showed FA laterality before adjusting for age,
>>> only a few voxels still showed FA laterality after adjusting for age
>>> ("tstat1.nii.gz"). I thought it means that age may have a somewhat great
>>> effect on FA lateraliy. But there were no positive or negative correlation
>>> ("tstat2.nii.gz", "tstat3.nii.gz"). It's so weird.
>>>
>>> Please tell me if you know my mistakes.
>>>
>>>
>>> Best regards,
>>> Akira Yogi
>>>
>>
>>
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>
>
>
> --
> Anderson M. Winkler
> FMRIB / Analysis Group
> [ Blog <http://brainder.org/> | Twitter
> <http://twitter.com/AndersonWinkler> ]
>
>
> ------------------------------
>
> IMPORTANT WARNING: This email (and any attachments) is only intended for
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> information that is privileged and confidential. You, the recipient, are
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> Unauthorized redisclosure or failure to maintain confidentiality may
> subject you to federal and state penalties. If you are not the intended
> recipient, please immediately notify us by return email, and delete this
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>
--
Anderson M. Winkler
FMRIB / Analysis Group
[ Blog <http://brainder.org/> | Twitter <http://twitter.com/AndersonWinkler>
]
