06 Review Exercises

Module 2 Probability & Reliability Statistics

Lesson M02-06

Participant Guide: Module 2 pages 42 & 43

Duration: 13 minutes

Successful completion of these exercises indicates you have a good grasp of the various reliability metrics and how they are related to the probability density function.  The exercises also cover the basic probability distributions and how they play a part in estimating reliability statistics.

Exercise Questions

1. How is the Cumulative Distribution Function (CDF) related to the Probability Density Function (PDF)?

2. How is the Cumulative Distribution Function (CDF) related to the Reliability Function?

3. What does the B10 life indicate?

4. The reliability of units supplied by two different suppliers could be compared by comparing their reported MTTFs (True/False).

5. The MTTF estimates the time at which about 50% of the population is expected to fail (True/False).

6. For an exponential distribution (constant failure rate), it is true that R(100) = R(200) (True/False).

7. Why would the times to failure for bearing wear likely not follow an exponential distribution?

8. An electronic device is modeled using a Weibull distribution. The parameters are estimated to be b = 0.73 and h = 1000 hours. What is the reliability at 500 hours?

9. For the previous problem, how does the reliability at 500 hours change if we add 100 hours of burn-in?