Mann Whitney U Test

Mann Whitney U Test

Mann Whitney U Test is located under Model Studio (   ) in Statistical Analysis below Hypothesis Test, under Non-Parametric Test in the left task pane. Use the drag-and-drop method or double-click to use the algorithm in the canvas. Click the algorithm to view and select different properties for analysis.


Properties of Mann Whitney U Test

The available properties of the Mann Whitney U Test are shown below.


The table below describes the different properties of the Mann Whitney U Test.

Field

Description

Remark

RunIt allows you to run the node.-
ExploreIt allows you to explore the successfully executed node.-
Vertical Ellipses

The available options are

  • Run till node
  • Run from node
  • Publish as a model
  • Publish code
-

Task Name

It is the name of the task selected on the workbook canvas.

  • You can click the text field to edit or modify the task's name.
  • Space between words is not allowed in the Task Name.

Group 1


It allows you to select the independent variable.

  • You need to select numeric data.
  • Only numeric columns are displayed in this dropdown.

Group 2


It allows you to select the independent variable.

  • You need to select numeric data.
  • Only numeric columns are displayed in this dropdown.

Advanced

Continuity

It tells if a continuity correction should be applied or not.

  • The default value is True.
    • True means that the method of continuity is asymptotic.
    • Asymptotic means that the ratio of the two distributions approaches unity as they approach the limit or infinity.


Alpha

It allows you to enter the alpha value or a significance level

  • You can modify this value.
  • Value of alpha always lies between 0 and 1.
  • The value 0 interprets 100% confidence on the test. The value 1 interprets 0% confidence on the test. The system cannot guarantee both scenarios; hence the values cannot be 0 and 1


Alternative

Defines the alternative hypothesis.

  • The default value is Two-sided. You can modify this value.
  • You can choose from –
    • Two-sided - the distributions are not equal.
    • Larger - underlying x distribution is stochastically less than the underlying y distribution.
    • Smaller - underlying x distribution is stochastically greater than the underlying y distribution.

Node Configuration


It allows you to select the instance of the AWS server to provide control over the execution of a task in a workbook or workflow.

For more details, refer to Worker Node Configuration.

Example of Mann Whitney U Test

As a medical researcher, you wish to compare two independent drugs, Drug 1 and Drug 2 on their level of effectiveness. You use the Mann Whitney U test to determine whether the two drugs differ in their effectiveness.


The data tab shows the selected input columns. These are the two numeric data groups that are used for the comparison.
Further, the Result page is as follows. 

The result page consists of the following sections:

1. Hypothesis:

This section displays Null Hypothesis and Alternative Hypothesis defined by the system.


2. Mann Whitney U Test:

This section displays the Mann Whitney U Test Rank test result. It shows value of the U Statistic, p Value and Alpha (α).


3.Interpretation:

In this example, the p value (0) is less than the alpha value (0.05); hence the null hypothesis is rejected. The rejection of the null hypothesis means that the population median of the first group differs from that of the second group.




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