1.

Leave Alpha as 0.05 (the chance of failing the test if the new process is as good as the target).

2.

Enter 4 as the Baseline Counts per Unit, indicating the target of 4 defects per wafer.

3.

Enter 1 as the Difference to detect.

4.

Enter a power of 0.9, which is the chance of detecting a change larger than 1 (5 defects per wafer). In this type of situation, alpha is sometimes called the producer’s risk and beta is called the consumer’s risk.

5.

Click Continue to see the results in Window For Counts Per Unit Example, showing a computed sample size of 38 (rounded to the next whole number).
