Data considerations for Probit Analysis

To ensure that your results are valid, consider the following guidelines when you collect data, perform the analysis, and interpret your results.

The response should be binary
Binary data have only two possible outcomes: the event (the item fails) or non-event (the item does not fail). If you have a continuous response that measures individual failure times, use Accelerated Life Testing.
You must have a stress variable
The stress variable defines the amount of stress that you put on an item during the pass/fail test. Use multiple stress values to test common stress loads. For example, to test a drill press that runs at 4 different speeds under normal-use conditions, you can include the 4 different stress levels in your test. Minitab treats the stress variable as a covariate. In addition to the stress variable, you can also enter a factor as a categorical predictor for the analysis.