## How do I interpret type 3 tests of mixed effects? (with photo)

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# How do I interpret type 3 tests of mixed effects? (with photo)

How do I interpret the following?

I know that because of the significant interaction, I shouldn't interpret lower order terms.

What is the significant interaction telling me? And if it weren't significant, what would the lower order terms tell me? That there's a difference between groups?

New to SAS and kind of new to stats - I appreciate the help!

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‎04-03-2018 10:35 AM
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Posts: 404

## Re: How do I interpret type 3 tests of mixed effects? (with photo)

The interaction indicates only that differences among the 3 DRUGs are not the same at all 7 TIMEHRs. It does not tell you anything about how or which means are different; you have to use post-hoc testing to sort that out. With a 3 x 7 factorial, the post-hoc testing is complex and (in my opinion) should be guided by the context of your study.

I would start by plotting the estimates of the interaction means. But then you'll need to learn a lot more about interpretation of ANOVA both with and without interaction. The topic is too complicated to address adequately in this Community forum. Good luck!

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Solution
‎04-03-2018 10:35 AM
PROC Star
Posts: 404

## Re: How do I interpret type 3 tests of mixed effects? (with photo)

The interaction indicates only that differences among the 3 DRUGs are not the same at all 7 TIMEHRs. It does not tell you anything about how or which means are different; you have to use post-hoc testing to sort that out. With a 3 x 7 factorial, the post-hoc testing is complex and (in my opinion) should be guided by the context of your study.

I would start by plotting the estimates of the interaction means. But then you'll need to learn a lot more about interpretation of ANOVA both with and without interaction. The topic is too complicated to address adequately in this Community forum. Good luck!

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