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What’s a Two Proportions Test?

The Two Proportions Test is a hypothesis tests that can be used to determine whether the proportion defective of one strata of a process is statistically different from the proportion defective (or yield) of another strata of a process. It is useful for determining whether a particular strata or group could provide insight into the root cause of process issues.

An example would be testing if the product defect rates are truly different for two separate production lines or whether the difference is due to random chance.

Learn more about One Proportion Tests in Analyze Phase, Module 4.2.2 of Black Belt Training.

How to Run a Two Proportions Test in Minitab

1. Select Raw Data:


2. Go to Stat > Basic Statistics > 2 Proportions:


3. Click “OK”:


4. Use the standard P-Value of .087

To learn more about Two Proportions Tests, register for Black Belt Training and review Analyze Phase, Module 4.2.2.