Leave Alpha as 0.05 (the chance of failing the test if the new process is as good as the target).
Enter 4 as the Baseline Counts per Unit, indicating the target of 4 defects per wafer.
Enter 1 as the Difference to detect.
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).
Window For Counts Per Unit Example

Help created on 9/19/2017