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Main Effects Power Analysis

Gil

New Contributor

Joined:

Nov 9, 2017

Spoiler
 

I have a question  regarding design evaluation in JMP: when I'm running power analysis for main effects only, the power is higher for these effects then if I would do analysis with 2nd degree interactions. Do you know why the addition of interactions in the analysis will change the power of the main effects? 

2 REPLIES
David_Burnham

Super User

Joined:

Jul 13, 2011

Estimating the additional terms is consuming additional degrees of freedom, which will influence the power of estimation

 

powerdoe.PNG

-Dave
Gil

New Contributor

Joined:

Nov 9, 2017

Thanks David. It was helpful.