I don't think it is correct conceptually. By including SNR as a covariate, you are saying that you expect the thickness to increase with higher SNR and decrease with lower SNR. This does not make sense to me. It sounds like you are trying to do a mixed effects analysis where you weight by the SNR. Still, mathematically, this is not a true mixed effect analysis (which requires estimates of the within and between subject noise). `

On 8/3/18 10:57 AM, John Anderson wrote:

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Daer FS experts,

I would like to inquire about including SNR as a covariate for the between groups cpmparison in cortical thickness. Is this procedure correct mathematically? Do I need to demean the SNA values before including it covariates? Finally, do you recommend any quality parameters other than SNR to be included covariate?

I look forward to learn from your expertise,

Thanks,

John
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