Recommended Software for Wilcoxon-Mann-Whitney Test and Associated Confidence Interval
Use the
coin package in
R which also requires the
modeltools and
mvtnorm packages. Here is an example:
library(coin)
y <- c(1, 2, 2, 2, 2, 4, 2, 5, 8, 16)
g <- factor(c(1,1,1,1,1,1,2,2,2,2))
wilcox_test(y ~ g, conf.int=TRUE, distribution='exact') # omit distribution to get asymptotic
# Get location estimate another way
median(outer(y[g=='1'], y[g=='2'], '-'))
Output:
Exact Wilcoxon Mann-Whitney Rank Sum Test
data: y by groups 1, 2
Z = -2.0469, p-value = 0.07619
alternative hypothesis: true mu is not equal to 0
95 percent confidence interval:
-14 0
sample estimates:
difference in location
-4
[1] -4