st: Interaction of ANOVA contrast (e.g. linear/quadratic trend) and another Factor Variable?

[Jared Saletin <jsaletin@berkeley.edu>]

Hi all,

So I've used the anovalator and anovacontrast ado's to calculate ANOVA contrasts (mainly linear and quadratic trends) across levels of a factor variable (say Factor A). 

I was wondering if anyone knows how to calculate the interaction of that contrast (across A) and another factor (Factor B).

For instance in SPSS you can calculate the Linear  x B interaction, or the Quadratic x B interaction, to see if the linear or quadratic trend differs by the levels of A or B.

Don't see a way to get that interaction using the tools above.

Is it rather something that should be specified in the model explicitly?

Or perhaps defining it manually from the margins command?

Thanks so much for all the help!

Cheers,
Jared


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