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How to compare the Emms of two models?
Pairwise comparisons The most common follow-up analysis for models having factors as predictors is to compare the EMMs with one another. This may be done simply via the pairs () method for emmGrid objects. In the code below, we obtain the EMMs for source for the pigs data, and then compare the sources pairwise.
How to do pairwise comparisons in emmeans matrix?
The numerical main results associated with pairwise comparisons can be presented compactly in matrix form via the pwpm () function. We simply hand it the emmGrid object to use in making the comparisons:
Is it possible to make emmeans in R?
It has a very thorough set of vignettes (see the vignette topics here ), is very flexible with a ton of options, and works out of the box with a lot of different model objects (and can be extended to others ????). I’ve started recommending emmeans all the time to students fitting models in R.
How to calculate the p value in emmeans?
If TRUE, a detailed result is shown. an object of class emmeans_test. .y.: the y variable used in the test. group1,group2: the compared groups in the pairwise tests. statistic: Test statistic (t.ratio) used to compute the p-value. df: degrees of freedom. p: p-value. p.adj: the adjusted p-value.
What are the defaults for pairs in emmeans?
In its out-of-the-box configuration, pairs () sets two defaults for summary (): adjust = “tukey” (multiplicity adjustment), and infer = c (FALSE, TRUE) (test statistics, not confidence intervals). You may override these, of course, by calling summary () on the result with different values for these.
How are Emms subtracted for later factor levels?
In the example above, EMMs for later factor levels are subtracted from those for earlier levels; if you want the comparisons to go in the other direction, use pairs (pigs.emm.s, reverse = TRUE). Also, in multi-factor situations, you may specify by factor (s) to perform the comparisons separately at the levels of those factors.
Is there a noninferiority test for emmeans?
Options exist to switch off any one of these and to switch which triangle is used for the latter two. Also, optional arguments are passed. For instance, we can reverse the direction of the comparisons, suppress the display of EMMs, swap where the P values go, and perform noninferiority tests with a threshold of 0.05 as follows: