Analyzes the observed differences in the process median between two input settings. This test is similar to the 2-sampe t-test, and is an alternative for cases where the data from the two samples are not reasonably normal.
|When to Use||Purpose|
|Mid-project||Test which inputs have significant influence on the output by fixing an input at two different settings (levels).|
|End of project||Verify a significant difference exists between the medians of the pre-project process and the post-project, improved process. Of course, this step assumes one of the goals of the project was to shift the process median.|
Continuous Y (output), a single X (input) at two levels.