Six Sigma level implies how many defects per million?

• A. 67,000 defects per million
• B. 0 defects per million
• C. 10 defects per million
• D. 3.4 defects per million

Answer: (D)

Six Sigma uses defects per million opportunities to quantify quality. At the Six Sigma level, a process produces only about 3.4 defects per million opportunities, meaning roughly 99.99966% of opportunities are defect-free. This figure comes from the idea of a six-sigma process, with a practical long-term drift of about 1.5 sigma that lowers the ideal 6-sigma performance to 3.4 DPMO in real-world operation. The other options describe far higher defect rates or perfection, which don’t match the Six Sigma standard. So the Six Sigma level implies about 3.4 defects per million opportunities.