sjstats (version 0.17.6)

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(data, x, grp, distribution = "asymptotic", out = c("txt", "viewer",
  "browser"), encoding = "UTF-8", file = NULL)

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.

encoding

Character vector, indicating the charset encoding used for variable and value labels. Default is "UTF-8". Only used when out is not "txt".

file

Destination file, if the output should be saved as file. Only used when out is not "txt".

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

# NOT RUN {
data(efc)
# Mann-Whitney-U-Tests for elder's age by elder's dependency.
mwu(efc, e17age, e42dep)

# }