1. The predicted reliability is higher than the long term realized probability. Which of the following is the MOST likely cause of this difference ?

A. Deterioration of the manufacturing processes and procedures.

B. Lack of adequate employee training and process audits.

C. The accumulation of random process variations.

D. A poor initial estimation of reliability.


2. In a corrective action system, trend analysis can be defined as :

I. Long-term movement. III. A cyclical component of a time series.

II. The short term status of problems. IV.. Seasonal variations.

A. I only

B. II and III only

C. I, II and III only

D. I, II, III and IV


3. The MOST valid source of failure rate data is :

A. Test data obtained under very closely controlled conditions.

B. Environmental test data.

C. The manufacturing process.

D. Operational data.


4. A comprehensive failure analysis and corrective action feedback loop must determine :

I. What failedII. How it failedIII. Why it failed.

A. I only

B. I and II only

C. II and III only

D. I, II and III


5. What is this system’s reliability at 700 hours?

Where component failure data is :

– Failure rate of A = 0.0007 failures/hrReliability of B = 0.92

– MTTF of C = 1400 hours – Reliability of D = 0.85.

A 0.986

B. 0.998

C. 0.994

D. 0.952


6. Given mean-time-to-failure of 200 hours for each of two components, what is the probability of system failure if both components operate in parallel for one hour ?

A. P = 0.010

B. P = 0.005

C. P = 0.001

D. P = 0.000025


7. Reliability prediction is :

A. A one time estimation process.

B. A continuous process starting with paper predictions.

C. More important than reliability attained in the field.

D. A popular method as simulation theory.


8. Ideally for a FRACAS to be effective, how many failures should be allowed to pass before corrective action is to be undertaken ?

A. First occurrence of a failure mode.

B. Second occurrence of a failure mode.

C. Third occurrence of a failure mode.

D. Fourth occurrence of a failure mode.


9. All of the following Boolean algebra expression are incorrect EXCEPT ?

A. 1 + 1 = 2

B. 1 – 1 = 1

C. 1 – 0 = 0

D. 1 + 0 = 1


10. What is the MOST accurate method to verify that the maintainability requirement of a design is being met ?

A. By analysis of the design.

B. By performing maintainability prediction.

C. By thorough design reviews.

D. By demonstration at the customer’s facility.


Picture © B. Poncelet

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