Hi - no, if EV3 is just there as an extra covariate to model the age
dependency you would not switch the sign of the second group. If you
want to model the two groups' age dependencies separately you would
have two separate EVs, each containing the demeaned age values of the
respective group, before then padding with zeros for the other group.
Cheers.
On 13 Oct 2008, at 22:54, Tonya White wrote:
> Greetings, I have a question about group comparisons using
> covariates and
> specifically, related to a series of posts from the archives (Jun
> 2007). In
> the example presented below (from the archives), where age was being
> used as
> the covariate, do you switch the sign of EV3 for the second group? I
> ask
> because when you run the between group analyses, you set group 1 >
> group 2
> as [1 -1]. Thanks, Tonya
>
>>>>
>>>> Group EV1(group1) EV2 (group2) EV3 (age )
>>>> 1 1 0 3
>>>> 1 1 0 1
>>>> 1 1 0 -2.5
>>>> 1 1 0 4
>>>> 1 0 1 -1
>>>> 1 0 1 2
>>>> 1 0 1 1.7
>>>> 1 0 1 1.5
>
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