One-Sample Equivalence Test

Test

  

In addition to the confidence interval (CI) for the difference, Minitab also performs a hypothesis test. If you use the default method to calculate the CI, then both the test and the CI lead to the same conclusion about claiming equivalence.

The results for the hypothesis test include p-values for two separate null hypotheses:

·    The difference is less than or equal to your lower limit for equivalence.

·    The difference is greater than or equal to your upper limit for equivalence.

If both null hypotheses are rejected, then the difference falls within your equivalence interval and you can claim that the product or process mean is equivalent to the target value.

Example Output

Test

 

Null hypothesis:         Difference ≤ -0.42 or Difference ≥ 0.42

Alternative hypothesis:  -0.42 < Difference < 0.42

α level:                 0.05

 

Null Hypothesis     DF   T-Value  P-Value

Difference ≤ -0.42  27    5.0972    0.000

Difference ≥ 0.42   27  -0.97605    0.169

 

The greater of the two P-Values is 0.169. Cannot claim equivalence.

Interpretation

For the snack bag analysis, the highest p-value is 0.169, which is greater than the a level of 0.05. These results indicate that the difference is not within your equivalence limits of -0.42 and 0.42. Thus you cannot claim that the force that is required to open the new bags is equivalent to the target value.