Statistical Quality Control, 7th Edition

Answers toSelected Exercises

CHAPTER 3

3.1.   (a) = 16.029. (b) s = 0.0202.

3.5.   (a) = 952.9. (b) s = 3.7.

3.7.   (a) = 121.25. (b) s = 22.63.

3.15.   Both the normal and lognormal distributions appear to be reasonable models for the data.

3.17.   The lognormal distribution appears to be a reasonable model for the concentration data.

3.23.   (a) = 89.476. (b) s = 4.158.

3.27.   sample space: {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}

3.29.   (a) 0.0196. (b) 0.0198.

(c) Cutting occurrence rate reduces probability from 0.0198 to 0.0100.

3.31.   (a) k = 0.05. (b) µ = 1.867, σ² = 0.615.

(c) F(x) = {0.383; x = 1   0.750; x = 2 1.000; x = 3

3.33.   (a) Approximately 11.8%. (b) Decrease profit by $5.90/calculator.

3.35.   Decision rule means 22% of samples will have one or more nonconforming units.

3.37.   0.921

3.43.   (a) 0.633. (b) 0.659. Approximation is not satisfactory.

(c) n/N = 0.033. Approximation is satisfactory.

(d) n = 11

3.45.   Pr{x = 0} = 0.364, Pr{x ≥ 2 } = 0.264

3.47.   Pr{