Another company makes 1,000,000 parts. They’re shooting for 3 sigma quality. How many defective parts would there be?
Explanation
Answer: C - Three sigma implies that 99.73% fall within standards, or less than 2,700 defects per million.
For the basis of comparison:
1 sigma is 68.26%. This would be 317,400 defects per million.
2 sigma is 95.46%. This would be 45,400 defects per million.
3 sigma is 99.73%. This would be 2,700 defects per million.
6 sigma is 99.99985%, or less than 2 defects per million.
Key takeaway: Three sigma is a realistic representation of good quality in most manufacturing processes. Most organizations will find a range between two and three sigma as a cost-effective point.
