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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 Two Proportions Tests in Analyze Phase, Module 4.2.2 of Black Belt Training.

How To Run A Two Proportions Test In SigmaXL

Download the Two Proportions Test Data Set for SigmaXL here.

1. Select Raw Data:


2. Data Table:


3. Go to Statistical Tools > Basic Statistical Templates > 2 Proportions Test & Confidence Interval:


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