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I have a question about emmeans

  • Variables are A = {a1, a2, a3}, B= {b1, b2}, C = {c1, c2}
  • Model ~ A+B+C+A * B+A * C+C * B
  • One of research questions: Is there an effect of C on a1, a2 und a3 (A)?

And I was doing an analysis with > emmeans (Model, ~C|A+B) cause I needed to do also with "pairs" (for contrast analysis)

Also emmeans is for "mean" and pairs is for "comparison of mean" I can interpret and report values for pairs cause there are t-values and p-values ex. t(45) = 0.35, p = .003. The effect of C is significant

But I don't get it to interpret emmeans. How can I interpret this table and report the values? Could you please explain how I can do?

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A comprehensive overview van be found here: https://cran.r-project.org/web/packages/emmeans/vignettes/interactions.html

Calling emmeans(Model, simple = "each") will give you a straightforward table with each possible combination of your factors. Be careful in jumping in with calling complex contrast without first visualizing your results; you might overlook crucial interaction impacts, potentially rendering your interpretation invalid.

BTW, which package have you used for fitting the model? Typically, the notation e.g. A*B entails both main effect and interaction (A+B+A:B), so verify your model formulation.

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  • $\begingroup$ Thanks a lot before posting this question I have already tried to find for this with Google and I read what you linked before that. Nevertheless I cannot get it how to interpret so I did post this question well, I will try to keep working with that... And about your question, yes you're right I meant Model ~ A+B+C+A:B+A:C+C:B :) Thanks for your answer! $\endgroup$
    – Taede17
    Commented Aug 13, 2021 at 13:37
  • $\begingroup$ You get a comparison of the estimated marginal means. What is the interpretation problem, precisely? $\endgroup$
    – KrisBae
    Commented Aug 13, 2021 at 21:16
  • $\begingroup$ Cause I have never had experience with emmeans so I don't know even how I should report this ex. with t-test I know that I should report so; t(35) = 5.76, p = .007 and this tell us that the factor A has an effect and this is significant but with emmeans what I know exactly is emmeans tell us mean values that's all. I just want to learn how I should report with values from emmeans table and which values are important for report. You wrote "you get a comparison of the estimated marginal means" I cannot interpret or understand the table just with your comment. I am just trying to learn. Thanks $\endgroup$
    – Taede17
    Commented Aug 14, 2021 at 2:11
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    $\begingroup$ The issue really isn't with understanding the software. I think you need to talk to a statistical consultant. Check with a stat or biostat dept near you. $\endgroup$
    – Russ Lenth
    Commented Aug 15, 2021 at 13:22
  • $\begingroup$ I think what was meant in this answer was pairs(emmeans(Model, ~ A*B*C), simple = "each"). This will show pairwise. comparisons of each factor, broken down by the other two factors. $\endgroup$
    – Russ Lenth
    Commented Aug 16, 2021 at 2:33

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