 |
1 | |
Reliabilities are typically specified with respect to normal operating conditions. |
|
| | A) | True |
| | B) | False |
|
2 | |
If a system is made up of two components that are in series, and both have failure rates of 50%, the probability that the system will fail is 75%. |
|
| | A) | True |
| | B) | False |
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3 | |
The probability that a serial system will work is the sum of the probabilities that each component will work divided by the number of components.. |
|
| | A) | True |
| | B) | False |
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4 | |
Adding three or more identical backup systems will assure 100% reliability. |
|
| | A) | True |
| | B) | False |
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5 | |
The costs of backup systems need to be balanced against the costs of failure. |
|
| | A) | True |
| | B) | False |
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6 | |
A system is composed of three components, A, B and All three of these components must function in order for the system to work. Their reliabilities are respectively: A, 0.4; B1, 0.5; C, 0.5. The overall system reliability is: |
|
| | A) | 0.70 |
| | B) | 0.99 |
| | C) | 0.10 |
| | D) | 1.40 |
| | E) | 0.97 |
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7 | |
A life test has shown that coffeemakers fail in use at the rate of 0.04257 per month. The manufacturer warranties that a coffeemaker will last for 12 months of ordinary usagWhat is the reliability of any individual coffeemaker? |
|
| | A) | 0.4 |
| | B) | 0.5 |
| | C) | 0.6 |
| | D) | 0.7 |
| | E) | 0.8 |
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8 | |
A system is composed of two parts which must both operate in order for the system to perform as intendeThe parts have reliabilities of .6 and .5. There is an identical backup system connected to the main system by a switch which has a reliability of .9. The probability that the overall system will operate is closest to: |
|
| | A) | .30 |
| | B) | .40 |
| | C) | .50 |
| | D) | .60 |
| | E) | .70 |
|
9 | |
If the transformer has a mean time to wear-out of 20 years with a standard deviation of 2 years, what is the probability that it will wear out within 19 years? |
|
| | A) | 0.1915 |
| | B) | 0.3085 |
| | C) | 0.383 |
| | D) | 0.5 |
| | E) | 0.6915 |
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10 | |
Four major components - video, audio, tuner and power supply - make up a big screen television set. All must function for the set to be accepted for shipment to customers. Reliabilities for each major component are 80%. What is the probability that a newly made set will be accepted for shipment? |
|
| | A) | 10.25% |
| | B) | 80% |
| | C) | 41% |
| | D) | 20% |
| | E) | Can't determine without further information |