Deck 6: Supplement: Reliability

Question 1

20)Which of the following statements is false?

A)When a system has availability,it doesn't necessarily mean that it also has high reliability.
B)Reliability considers the time it takes for a component or system to fail while it is operating.
C)Reliability takes into account any downtime associated with the repairs the system may need.
D)Reliability does not take into account the time it takes to make the component or system available for use.

Answer 1

C

Question 2

5)The computation of the reliability of the system assumes that the reliabilities of the individual components are ______ events.

A)mutually exclusive
B)dependent
C)joint
D)independent

Answer 2

D

Question 3

9)Calculate and indicate the composite reliability of Component 2 for the system shown in the following figure:

A)0.90
B)0.95
C)0.99
D)0.97

Answer 3

C

Question 4

3)The overall reliability of the system is the ______.

A)sum of the reliabilities of the individual components
B)minimum reliability of the individual components
C)product of the reliabilities of the individual components
D)maximum reliability of the individual components

Question 5

14)An electrical power system consists of four major components with reliabilities of 0.99,0.94,0.92,and 0.95.In order to improve the reliability,a backup component of reliability 0.92 is added to Component 3.Compute and indicate the overall reliability of the system.

A)0.87
B)0.88
C)0.99
D)0.88

Question 6

12)An electrical power system consists of four major components with reliabilities of 0.99,0.90,0.80,and 0.95.If the designers want to improve the reliability of the system by adding a backup component,which component should get the backup to achieve the highest reliability?

A)Component 1
B)Component 2
C)Component 3
D)Component 4

Question 7

17)Consider a lawn mower that fails six times in 240 hours of operation.The mean time between failures (MTBF)of the lawn mower is ______.

A)33 hours
B)45 hours
C)50 hours
D)40 hours

Question 8

4)Consider a product that has three components arranged in series as shown in the following figure: Calculate and indicate the overall reliability of the system.

A)0.857
B)0.986
C)0.727
D)0.675

Question 9

8)In the context of redundancy,the duplicate systems operate ______ the original component.

A)independently from
B)prior to
C)in parallel with
D)in a sequence with

Question 10

11)An electrical power system consists of four major components with reliabilities of 0.99,0.90,0.80,and 0.95.Compute and indicate the overall reliability of the electrical power system.

A)0.8125
B)0.9856
C)0.7645
D)0.6772

Question 11

7)The duplication of critical components that serve as backup if the original component or subsystem fails is called ______.

A)availability
B)redundancy
C)maintainability
D)reliability

Question 12

10)Calculate and indicate the overall reliability of the system shown in the following figure:

A)0.7994
B)0.8764
C)0.7896
D)0.9874

Question 13

13)An electrical power system consists of four major components with reliabilities of 0.99,0.94,0.92,and 0.95.In order to improve the reliability,a backup component of reliability 0.92 is added to Component 3.Compute and indicate the composite reliability of Component 3.

A)0.89
B)0.99
C)0.98
D)0.92

Question 14

19)______ is the ease with which an equipment or system can be repaired or serviced.

A)Availability
B)Maintainability
C)Redundancy
D)Reliability

Question 15

2)The key phrase in the definition of reliability is______.

A)probability that a component,product,or system can perform its function
B)under a given set of normal operating conditions of its use
C)perform its intended function
D)conditions of use

Question 16

18)______ is the percentage of times that a system or equipment is operating properly when it is needed for use.

A)Availability
B)Maintainability
C)Redundancy
D)Reliability

Question 17

6)The concept of independence in context of reliability implies ______.

A)the working or failing of one component does not affect the probability of working or failing of any other component
B)the working or failing of one component affects the probability of working or failing of the successive component
C)the working or failing of one component affects the probability of working or failing of all components in sequence
D)the working or failing of one component does not affect the probability of working or failing of only the preceding component

Question 18

15)______ is the reliability of a product or component expressed as the average length of time elapsed before the product or component fails.

A)Mean time to repair (MTTR)
B)Mean time to failure (MTTF)
C)Mean time between failures (MTBF)
D)Mean time between repairs (MTBR)

Question 19

16)Consider a lawn mower that fails six times in 240 hours of operation.The failure rate of the lawn mower is ______.

A)0.025
B)0.040
C)0.020
D)0.030

Question 20

1)______ can be defined as the probability that a component,product,or system can perform its intended function over a period of time under a given set of normal operating conditions of use.

A)Reliability
B)Maintainability
C)Availability
D)Redundancy

Question 21

35)A product consists of two parts.The reliability of these parts are 0.98 and 0.86.Calculate and indicate product reliability.

A)84.3%
B)75.2%
C)69.1%
D)73.2%

Question 22

37)A product consists of four parts.The reliability of these parts are 0.96,0.86,0.74,and 0.44.Calculate and indicate product reliability.

A)26.9%
B)34.3%
C)23.2%
D)63.0%

Question 23

30)A consumer wants to choose a highly reliable TV service provider with minimum service disruptions.Based on the data given in the following table,determine which TV provider the consumer should choose.

A)Crescent TV Network
B)Horizon TV Network
C)Perseus TV Network
D)Direct TV Network

Question 24

24)In order to increase the availability of an equipment or system for use,reliability has to ______ with ______ maintainability.

A)decrease,constant
B)be constant,decreasing
C)increase,constant
D)be constant,constant

Question 25

40)A product consists of three components with reliability of 0.95,0.95,and 0.95,respectively.The second component has a backup with reliability of 0.95.Calculate and indicate product reliability.

A)0.90%
B)0.87%
C)0.76%
D)0.83%

Question 26

23)Mean time to repair (MTTR)is a quantitative metric for ______.

A)availability
B)maintainability
C)redundancy
D)reliability

Question 27

34)A product consists of three parts.The reliability of these parts are 0.97,0.98,and 0.86.Calculate and indicate product reliability.

A)81.8%
B)73.2%
C)75.2%
D)99.1%

Question 28

21)Availability is related to ______.

A)reliability only
B)maintainability only
C)reliability and maintainability
D)redundancy and reliability

Question 29

39)A product consists of four components with reliability of 0.85,0.99,0.88,and 0.89,respectively.The third and fourth components have backups with corresponding reliability of 0.88 and 0.89.Calculate and indicate product reliability.

A)0.82%
B)0.78%
C)0.63%
D)0.93%

Question 30

27)Products should be designed to ensure ______ time between failures.

A)short
B)equal
C)long
D)unequal

Question 31

26)A laser printer is able to operate 400 hours between two repairs,and the mean time to repair the printer is 4 hours.Compute and indicate the availability of the printer.

A)0.99
B)0.96
C)0.98
D)0.97

Question 32

29)Mars Industries assembles industrial machines using four components in series.Customers who purchases these machines require a reliability of 0.95.In order to achieve a reliability of 0.95,what should be the individual reliability of the individual components?

A)0.987
B)0.897
C)0.768
D)0.934

Question 33

32)A product consists of five parts.The reliability of these parts are 0.51,0.58,0.94,0.77,and 0.92,respectively.Calculate and indicate product reliability.

A)20%
B)30%
C)40%
D)50%

Question 34

38)A product consists of four parts.The reliability of these parts are 0.98,0.28,0.99,0.99,and 0.99.Calculate and indicate product reliability.

A)0.27%
B)0.32%
C)0.43%
D)0.21%

Question 35

25)The availability of an equipment or system is given by ______.

A)MTBF / MTTR
B)MTTR / MTBF
C)MTTR (MTBF - MTTR)
D)MTBF / (MTBF + MTTR)

Question 36

33)A product consists of six parts.The reliability of these parts are 0.94,0.9,0.56,0.99,0.77,and 0.96.Calculate and indicate product reliability.

A)34.7%
B)23.2%
C)14.1%
D)90.3%

Question 37

31)A product consists of six parts.The reliability of these parts are 0.82,0.73,0.79,0.00,0.98,and 0.85,respectively.Based on this information,we can say ______.

A)the product has a low probability of failure
B)the product will never fail
C)the product will always fail
D)the product has a low-to-medium probability of failure

Question 38

36)A product consists of six parts.The reliability of these parts are 0.97,0.95,0.99,0.93,0.91,and 0.85.Calculate and indicate product reliability.

A)65.6%
B)85.2%
C)86.1%
D)77.2%

Question 39

28)The implication for product designers is that as MTBF ______ and MTTR ______,availability also increases.

A)increases,increases
B)decreases,decreases
C)decreases,increases
D)increases,decreases

Question 40

22)Mean time between failures (MTBF)is a quantitative measure of ______.

A)availability
B)maintainability
C)redundancy
D)reliability

Question 41

44)A widget fails 12 times in 600 hours of operation.The failure rate of the widget is ______.

A)0.02
B)0.03
C)0.01
D)0.05

Question 42

43)Consider a chainsaw that fails five times in 100 hours of operation.The failure rate of the chainsaw is ______.

A)0.050
B)0.034
C)0.022
D)0.031

Question 43

57)In product design,simpler designs with fewer components are ______.

A)more likely to fail
B)likely to function with the same reliability as designs with more components
C)likely to improve reliability
D)more expensive to repair

Question 44

59)The reliability of a product or component can also be expressed as the ______.

A)maximum length of time elapsed before the product or component fails
B)average length of time elapsed before the product or component fails
C)minimum length of time elapsed before the product or component fails
D)range (difference between lowest and highest times)of time elapsed before the product or component fails

Question 45

60)The average length of time elapsed before the product or component fails is known as ______.

A)MTBF (mean time between failures)
B)MTBF (mean time of breakdown frequency)
C)MTTR (mean time to repair)
D)MTDT (mean time of downtime)

Question 46

55)The computation of the reliability of a system assumes that the reliability of a component in that system is ______.

A)independent of the reliabilities of all the other components
B)dependent on the reliabilities of some of the other components
C)dependent on the reliability of one of the other component
D)dependent on the reliabilities of all the other components

Question 47

53)Redundancy refers to ______.

A)the duplication of critical components such that the duplicate systems operate in parallel to the original components
B)the duplication of components across the entire system such that each component in the system is duplicated
C)the creation of a second system to mimic the first system if every component of the first system should fail
D)the creation of unnecessary backup systems to provide a level of operational reliability that is not really required

Question 48

61)Given the failure rate of a component,we can calculate MTBF as ______.

A)the range of the failure rate across many tested components
B)the standard deviation of the failure rate across many tested components
C)the square of the failure rate
D)the reciprocal of the failure rate

Question 49

52)The field of study that analyzes the likelihood of product and system failures over time is known as ______.

A)confidence analysis
B)reliability
C)redundancy
D)backup analysis

Question 50

49)A widget fails 12 times in 600 hours of operation.The MTBF of the widget is ______.

A)50 hours
B)45 hours
C)32 hours
D)31 hours

Question 51

42)A product consists of four components with reliability of 0.89,0.90,0.91,and 0.92,respectively.Each component has a backup with the same reliability.Calculate and indicate product reliability.

A)96.40%
B)86.31%
C)94.11%
D)79.32%

Question 52

41)A product consists of four components with reliability of 0.85,0.87,0.89,and 0.91,respectively.The first and third components each have a backup with reliability of 0.95 and 0.90,respectively.Calculate and indicate product reliability.

A)77.71%
B)62.80%
C)39.40%
D)89.10%

Question 53

46)A system fails 20 times in 800 hours of operation.The failure rate of the system is ______.

A)0.025
B)0.035
C)0.015
D)0.051

Question 54

45)A complicated widget fails 12 times in 600 hours of operation.The failure rate of the widget is ______.

A)0.02
B)0.03
C)0.01
D)0.05

Question 55

48)Consider a chainsaw that fails five times in 100 hours of operation.The MTBF is ______.

A)20 hours
B)30 hours
C)40 hours
D)15 hours

Question 56

56)In a system with multiple components,the overall reliability of the system ______.

A)is equal to the reliability of the component with the lowest reliability
B)is equal to the reliability of the component with the highest reliability
C)is significantly less than the reliability of the individual components
D)is significantly more than the reliability of the individual components

Question 57

51)A system fails 10 times in 100 hours of operation.The failure rate of the system is ______.

A)10 hours
B)29 hours
C)32 hours
D)55 hours

Question 58

50)A system fails 20 times in 800 hours of operation.The MTBF of the system is ______.

A)40 hours
B)29 hours
C)32 hours
D)55 hours

Question 59

58)A system has four components: A,B,C,and D.These components have reliability of 0.85,0.90,0.95,and 0.99,respectively.Which component should have a backup?

A)Component A
B)Component B
C)Component C
D)Component D

Question 60

54)The overall reliability of a system is ______.

A)the product of the reliabilities of its individual components
B)the sum of the reliabilities of its individual components
C)the minimum of the reliabilities of its individual components
D)the maximum of the reliabilities of its individual components

Question 61

65)Which of the following statements is true with regard to the terms reliability and availability?

A)If a system has high availability,it also has high reliability.
B)If a system has high availability,it then has low reliability.
C)Availability and reliability of a system refer to the same concept.
D)If a system has high availability,it does not necessarily mean that it also has high reliability.

Question 62

69)If MTBF represents mean time between failures,and MTTR represents mean time to repair,then availability is given by ______.

A)MTBF / MTTR
B)MTBF / (MTBF + MTTR)
C)MTBF / (MTBF - MTTR)
D)MTTR / MTBF

Question 63

82)A system fails 200 times in 8,000 hours of operation.The MTBF of the system is ______.

A)40 hours
B)29 hours
C)32 hours
D)55 hours

Question 64

72)A computer has a mean time between failures of 235 hours and mean time to repair of 9 hours.In this case,the availability is ______.

A)96.3%
B)79.3%
C)78.9%
D)93.8%

Question 65

62)Which of the following is NOT one of the usual methods by which manufacturers of new products can develop MTBF measures?

A)by conducting intensive product testing
B)by analyzing actual past experience of similar products
C)by analyzing known factors that cause product failures
D)by doing a consumer survey

Question 66

74)A widget has a mean time between failures of 218 hours and mean time to repair of 14 hours.In this case,the availability is ______.

A)94.0%
B)89.6%
C)77.3%
D)88.1%

Question 67

77)An industrial boiler has a mean time between failures of 344 hours and mean time to repair of 8 hours.In this case,the availability is ______.

A)97.7%
B)93.6%
C)87.3%
D)98.1%

Question 68

71)A drilling machine has a mean time between failures of 368 hours and mean time to repair of 9 hours.In this case,the availability is ______.

A)97.6%
B)89.7%
C)78.9%
D)93.8%

Question 69

81)Products should be designed ______.

A)to ensure long time between failures
B)to ensure long time to repair
C)to ensure long downtimes
D)to ensure long develop times

Question 70

67)Maintainability refers to ______.

A)the ease with which an equipment or system can be repaired or serviced
B)the meantime between failures
C)the time a system is available for use when needed
D)the downtime experienced by a system

Question 71

76)A welding machine has a mean time between failures of 289 hours and mean time to repair of 10 hours.In this case,the availability is ______.

A)96.7%
B)93.6%
C)87.3%
D)98.1%

Question 72

79)A table saw has a mean time between failures of 313 hours and mean time to repair of 2 hours.In this case,the availability is ______.

A)95.1%
B)99.4%
C)81.7%
D)97.8%

Question 73

63)Which of the following is NOT one of the benefits of setting reliability goals?

A)contributes to success of the product in the marketplace
B)contributes to production efficiency
C)reduces equipment failures and waste
D)changes elasticity of supply

Question 74

64)Availability of a system refers to the ______.

A)percentage of the time that a system is operating properly when it is needed for use
B)percentage of the time that a system is down for maintenance
C)percentage of components in the system that have a backup component
D)percentage of the time that a system is available for use by the department that owns it (and is not being used by other departments)

Question 75

70)A sewing machine has a mean time between failures of 296 hours and mean time to repair of 11 hours.In this case,the availability is ______.

A)96.4%
B)92.1%
C)89.3%
D)78.9%

Question 76

80)A machine has a mean time between failures of 514 hours and mean time to repair of 19 hours.In this case,the availability is ______.

A)96.4%
B)99.2%
C)81.7%
D)97.8%

Question 77

66)Which of the following terms only considers the time it takes for a system to fail while it is operating but does not take into account any downtime associated with the repairs the system may need?

A)reliability
B)availability
C)redundancy
D)maintainability

Question 78

73)A typewriter has a mean time between failures of 420 hours and mean time to repair of 14 hours.In this case,the availability is ______.

A)96.8%
B)89.6%
C)77.3%
D)88.1%

Question 79

75)A hair dryer has a mean time between failures of 822 hours and mean time to repair of 1 hour.In this case,the availability is ______.

A)99.9%
B)93.6%
C)87.3%
D)98.1%

Question 80

68)Which of the following statements is true with regard to relationships between reliability,maintainability,and availability?

A)If maintainability is constant and reliability increases,then availability decreases.
B)If maintainability is constant and reliability decreases,then availability increases.
C)If maintainability is constant and reliability decreases,then availability decreases.
D)If maintainability increases,then reliability decreases but availability increases.