M.Sc. DEGREE EXAMINATION, NOVEMBER/DECEMBER 2017.
Third Semester
OR SQC
RELIABILITY THEORY
2 21233 A
Time 3 Hours Max. Marks 70
SECTION — A
Answer any FIVE questions. 6 30 Marks)
1. Define reliability. How do you link it with field failure data?
2. What are the causes of early failures? Describe a method for eliminating them.
3. Obtain the reliability function of log-normal failure density.
4. Obtain 95% confidence interval for the scale parameter in a Weibull failure model
when the shape parameter is known.
5. Explain the types of Censoring with suitable examples.
6. Discuss m.l method of estimating the gamma parameters in failure-censored
sampling.
7. Explain series configuration and obtain its reliability with a linearly increasing
hazard.
8. Explain MTTR and MTTF and compare them.
SECTION — B
Answer ALL questions. 10 40 Marks)
9. Explain reliability measures. Obtain reliability in terms of hazard rate and
failure density.
Or
Describe bath-tub curve and its characteristics. Show that exponential
distribution has a constant hazard rate.

10. Discuss the m.l method of estimating the reliability function of a
two-parameter Weibull failure model.
Or
Explain the interval estimation of reliability function in the case of an
exponential failure model.
11. Explain the m.l method of estimating the reliability function of normal failure
model in the case of failure censored samples.
Or
Explain the estimation of reliability function for one parameter exponential
failure model under failure-censored sampling and time-sensored
sampling.
12. Describe system availability measures. Obtain the reliability of parallel
and K out of N system with exponential components.
Or
Explain Markow analysis for a system with two independent components.
Discuss the types of availability.
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