Asq Certified Quality Auditor CQA · Free Practice Question Medium

Question 23

A process has a process mean (µ) of 50, a standard deviation (σ) of 3, an upper specification limit (USL) of 62, and a lower specification limit (LSL) of 38. What is the process performance index (Cpk)?
  • A 1.5
  • B 1.67
  • C 1
  • D 1.33
Reveal correct answer

Correct answer: D

Explanation

Cpk = min[(USL - µ) / (3σ), (µ - LSL) / (3σ)]

= min[(62 - 50) / (3 × 3), (50 - 38) / (3 × 3)]

= min[12 / 9, 12 / 9] ≈ 1.33

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