Reliability, Maintainability and Risk, 8th Edition

Appendix 8. Answers to Exercises

Chapter 2

(a)	(b)
1.114	1.1
2.0.99	0.42 (0.12*)
3.10–5	10–3
4.2.2×10–3	0.18 (0.22*)
5.Negligible	Negligible
6.Unavailability×2	Unavailability×2
*Beware the approximation. λt is large (i.e. 0.876). Furthermore, if the 10 000 hr per year approximation were used, then λt=1.

Chapter 5

1. Accumulated time T=50×100=5000 hr. Since the test was time truncated n=2(k+1).

Therefore,

(a)n=6, T=5000, α=0.4. From Appendix 2, χ²=6.21

(b)n=2, T=5000, α=0.4. From Appendix 2, χ²=1.83

2. If k=0 then n=2 and since confidence level=90%, α=0.1

Therefore ...