Equivalence Testing Overviewsee also
Equivalence Testing OverviewYou can use an equivalence test to determine whether the means for product measurements or process measurements are close enough to be considered equivalent.
Small differences between products are not always functionally or practically important. For example, a difference of 1 mg in a 200 mg dose of a drug is unlikely to have any practical effect. When you use an equivalence test, you specify how large the difference must be to be considered important. Smaller differences are considered unimportant. Minitab then tests two separate null hypotheses:
If both null hypotheses are rejected, then the difference falls within your equivalence interval and you can claim that the means for the products are equivalent.
This information is also conveyed graphically in an equivalence plot. If the confidence interval for the difference is completely within your equivalence limits, then you can claim equivalence.
Minitab provides four equivalence tests:
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Test |
Use to ... |
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Compare the mean of a product or a process to a standard. | |
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Compare two product means or two process means using 2 independent samples. | |
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Compare two product means or two process means when observations are paired, such as when measurements for two treatments are taken from the same person or part. | |
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Compare treatment means for data that was collected in a 2x2 crossover study. 2x2 crossover studies are commonly used to test whether individual participants experience equivalent effects on 2 different drugs. |