Field of application: a count-based quality metric (Y) following a Poisson distribution. For example: defects per PC, holds per telephone call, errors per document, etc.
Here we determine the expected (probabilistic) defect rate from what is observed in a sample. The calculation also gives the margin of error (statistical precision) on that expected defect rate (normal approximation method). Enter the following data:
- n: sample size
- λ̂: the occurrence rate in the sample; typically defects per unit (DPU).

