displayPairs {s20x} | R Documentation |
Display within-level pairwise comparisons for saturated two-way ANOVA model.
Description
Displays within-level pairwise comparisons from a two-way ANOVA with
interactions. Note that this is just a display function: it ignores any
cross-level pairs included in allpairs
, even though these will have
contributed to the computations for the Tukey adjustments. The purpose is
just to organise the output from emmeans
into a more convenient
format.
Usage
displayPairs(allpairs, levels1, levels2, brief = TRUE, asDF = FALSE)
Arguments
allpairs |
pairwise output from a command like |
levels1 |
a character string specifying which within-level comparisons
from |
levels2 |
a character string specifying which within-level comparisons
from |
brief |
either |
asDF |
either |
Details
allpairs
is a pairwise output from a command like
pairs(emmeans(fit, ~factor1 * factor2))
. If allpairs
is not
already a data.frame
it will be converted to a data.frame
within this function. It must contain a column called contrast
with
text descriptions like 'lev1 lev2 - lev3 lev4'
etc. levels1
and levels2
are character strings specifying which within-level
comparisons are wanted, and in which order. They must match the order
specified in emmeans
, so if using emmeans(fit, ~factor1 *
factor2)
then levels1
must belong to factor1
and
levels2
must belong to factor2
. All this function does is to
pick out the rows of allpairs
with the requested contrasts, so if
there are no contrasts of the requested format (e.g. because levels1
and levels2
have been switched) it will output a blank list. If
brief = TRUE
, columns labelled df
, SE
, and
t.ratio
or z.ratio
will be removed for a more succinct
display. If asDF = TRUE
, the output is returned as a data-frame
suitable for further manipulation, whereas if asDF = FALSE
it is
returned as a list for display only.
Author(s)
Rachel Fewster
Examples
## Fit a two-way ANOVA to the arousal data in arousal.df.
## The factors are gender (female, male) and picture shown to
## subject (infant, landscape, nude.f, nude.m):
data(arousal.df)
arousal.fit = lm(arousal ~ gender * picture, data = arousal.df)
## Create a data-frame with all pairwise comparisons using \code{emmeans}:
require(emmeans)
arousal.allpairs = pairs(emmeans(arousal.fit, ~gender * picture), infer = TRUE)
## Display only the within-level comparisons:
displayPairs(arousal.allpairs, levels1 = c('female', 'male'),
levels2 = c('infant', 'landscape', 'nude.f', 'nude.m'))