Test a null hypothesis involving the difference between randomly selected values from two samples by performing a two-sample Wilcoxon or Mann-Whitney U test.
Details
The Mann-Whitney U test is used to compare whether there is a difference in the dependent variable for two independent groups. Select a numerical test variable (test_var) and a categorical grouping variable (group_var).
Output
The first section of the output is the printed output of a wilcox.test run in R. There are more details on this printed output in the R documentation for wilcox.test. The output also includes a boxplot comparing the distributions of the selected groups. 
Parameters
| Variable name | Required | Constraints | Description |
|---|---|---|---|
| test_var | Yes | Column Input. Integer, Decimal | Numerical variable upon which the test will be computed. |
| group_var | Yes | Column Input. Text, Integer, Boolean, Date, DateTime | Categorical variable which provides the two independent samples. |
| mu | Yes | Decimal |
The null hypothesis is that the distributions of the samples differ by a location shift of mu
|
| alternative | Yes | Text, three options. | Select between a two sided and one-sided test by choosing either two.sided, greater or less. |
| confidence_level | Yes | Decimal between 0.5 and 0.99 | Set your confidence interval, default to 0.95. |