emmeans (version 1.3.2)

plot.emmGrid: Plot an emmGrid or summary_emm object

Description

Methods are provided to plot EMMs as side-by-side intervals, and optionally to display “comparison arrows” for displaying pairwise comparisons.

Usage

# S3 method for emmGrid
plot(x, y, type, intervals = TRUE,
  comparisons = FALSE, alpha = 0.05, adjust = "tukey",
  int.adjust = "none", frequentist, ...)
# S3 method for summary_emm
plot(x, y, horizontal = TRUE, xlab, ylab, layout,
  ...)

Arguments

x

Object of class emmGrid or summary_emm

y

(Required but ignored)

type

Character value specifying the type of prediction desired (matching "linear.predictor", "link", or "response"). See details under summary.emmGrid.

intervals

Logical value. If TRUE, confidence intervals are plotted for each estimate.

comparisons

Logical value. If TRUE, “comparison arrows” are added to the plot, in such a way that the degree to which arrows overlap reflects as much as possible the significance of the comparison of the two estimates. (A warning is issued if this can't be done.)

alpha

The significance level to use in constructing comparison arrows

adjust

Character value: Multiplicity adjustment method for comparison arrows only.

int.adjust

Character value: Multiplicity adjustment method for the plotted confidence intervals only.

frequentist

Logical value. If there is a posterior MCMC sample and frequentist is non-missing and TRUE, a frequentist summary is used for obtaining the plot data, rather than the posterior point estimate and HPD intervals. This argument is ignored when it is not a Bayesian model.

...

Additional arguments passed to update.emmGrid or dotplot

horizontal

Logical value specifying whether the intervals should be plotted horizontally or vertically

xlab

Character label for horizontal axis

ylab

Character label for vertical axis

layout

Numeric value passed to dotplot

Details

If any by variables are in force, the plot is divided into separate panels. These functions use the dotplot function, and thus require that the lattice package be installed. For "summary_emm" objects, the … arguments in plot are passed only to dotplot, whereas for "emmGrid" objects, the object is updated using … before summarizing and plotting.

In plots with comparisons = TRUE, the resulting arrows are only approximate, and in some cases may fail to accurately reflect the pairwise comparisons of the estimates -- especially when estimates having large and small standard errors are intermingled in just the wrong way. Note that the maximum and minimum estimates have arrows only in one direction, since there is no need to compare them with anything higher or lower, respectively.

If adjust or int.adjust are not supplied, they default to the internal adjust setting saved in pairs(x) and x respectively (see update.emmGrid).

Examples

# NOT RUN {
warp.lm <- lm(breaks ~ wool * tension, data = warpbreaks)
warp.emm <- emmeans(warp.lm, ~ tension | wool)
plot(warp.emm)
plot(warp.emm, by = NULL, comparisons = TRUE, adjust = "mvt", 
     horizontal = FALSE)
# }