They might be very similar if there is not effect of genotype or the effect is orthogonal to age.

On 10/30/2017 03:39 AM, hiroki.sato@med.tohoku.ac.jp wrote:

Dear experts

I'm using Qdec. I want to check regions where age and thickness are correlated, and regions where the thickness-age correlation differ between genotype(Hetero or WT).

When I choose "genotype(Hetero or WT)" as Fixed factors and "age" as Continuous variables, I can choice the results "Does the correlation between thickness and age, accounding for genotype, differ from zero" and "Does the thickness-age correlation differ between Hetero and WT?".

I have two questions.

Is "Does the correlation between thickness and age, accounding for genotype, differ from zero" equal to the results of "Does the correlation between thickness and age differ from zero" that I choose only "age" as Continuous variables? I don't know the meaning of "accounding for genotype" but these two results are almost same. Does just a little different results come from the difference of Degrees Of Freedom?

Thank you in advance.

Best, Hiroki

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