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sjstats (version 0.7.1)

mwu: Mann-Whitney-U-Test

Description

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(x, grp, distribution = "asymptotic", weight.by = NULL)

Arguments

x
Numeric vector or variable.
grp
Grouping variable indicating the groups that should be used for comparison.
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.
weight.by
Vector of weights that will be applied to weight all observations. Must be a vector of same length as the input vector. Default is NULL, so no weights are used.

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.

Examples

Run this code
data(efc)
# Mann-Whitney-U-Tests for elder's age by elder's dependency.
mwu(efc$e17age, efc$e42dep)

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