This function performs a Mann-Whitney-U-Test (or Wilcoxon rank sum test,
see wilcox.test and wilcox_test)
for x, for each group indicated by grp. If grp
has more than two categories, a comparison between each combination of
two groups is performed.
The function reports U, p and Z-values as well as effect size r
and group-rank-means.
Usage
mwu(data, x, grp, distribution = "asymptotic", out = c("txt", "viewer",
"browser"))
Arguments
data
A data frame.
x
Bare (unquoted) variable name, or a character vector with the variable name.
grp
Bare (unquoted) name of the cross-classifying variable, where
x is grouped into the categories represented by grp,
or a character vector with the variable name.
distribution
Indicates how the null distribution of the test statistic should be computed.
May be one of "exact", "approximate" or "asymptotic"
(default). See wilcox_test for details.
out
Character vector, indicating whether the results should be printed
to console (out = "txt") or as HTML-table in the viewer-pane
(out = "viewer") or browser (out = "browser"), of if the
results should be plotted (out = "plot", only applies to certain
functions). May be abbreviated.
Value
(Invisibly) returns a data frame with U, p and Z-values for each group-comparison
as well as effect-size r; additionally, group-labels and groups' n's are
also included.