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.
mwu(x, dv, grp, distribution = "asymptotic", weight.by = NULL,
out = c("txt", "viewer", "browser"))A (grouped) data frame.
Name of the dependent variable, for which the mean value, grouped
by grp, is computed.
Factor with the cross-classifying variable, where dv is
grouped into the categories represented by grp. Numeric vectors
are coerced to factors.
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.
Name of variable in x that indicated the vector of
weights that will be applied to weight all observations. Default is
NULL, so no weights are used.
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.
(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.
# NOT RUN {
data(efc)
# Mann-Whitney-U-Tests for elder's age by elder's dependency.
mwu(efc, e17age, e42dep)
# }
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