Learning Outcome:  Apply basic statistical process control (SPC) methods

Managing Quality: Integrating the Supply Chain, 5e (Foster)

Chapter 11   Statistically Based Quality Improvement for Variables

1) ________ is a decision-making skill demonstrated by the ability to draw conclusions based on data.

A) Data interlinking

B) Process benchmarking

C) Rational subgrouping

D) Statistical thinking

E) Qualitative modeling

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

2) ________ is based on the concept that all work occurs in a system of interconnected processes.

A) Statistical thinking

B) Qualitative modeling

C) Process benchmarking

D) Rational subgrouping

E) Data interlinking

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

3) Producer's risk is also called a ________ error.

A) type I

B) non-response

C) type II

D) processing

E) response

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

4) Consumer's risk is also called a ________ error.

A) processing

B) non-response

C) type II

D) response

E) type I

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

5) ________ is the probability that a good product will be rejected.

A) Retailer's risk

B) Consumer's risk

C) Manufacturer's risk

D) Management's risk

E) Producer's risk

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

6) ________ is the probability that a nonconforming product will be available for sale.

A) Producer's risk

B) Consumer's risk

C) Retailer's risk

D) Management's risk

E) Manufacturer's risk

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

7) ________ happens when statistical quality analysis fails to result in the scrapping or reworking of a defective product.

A) Management's risk

B) Producer's risk

C) Manufacturer's risk

D) Retailer's risk

E) Consumer's risk

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

8) ________ variation is centered on a mean and occurs with a somewhat consistent amount of dispersion.

A) Nonrandom

B) Specific

C) Systematic

D) Abnormal

E) Random

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

9) Which of the following is true of random variation?

A) It has a cause that can be identified.

B) It can be easily controlled.

C) It occurs with a somewhat consistent amount of dispersion.

D) It results in a process that is not repeatable.

E) It results from a shift in a process mean or some unexpected occurrence.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

10) ________ variation results from some event, such as shift in a process mean or some unexpected occurrence.

A) Uncontrollable

B) Nonrandom

C) Stochastic

D) Random

E) Indefinite

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

11) Which of the following is true of nonrandom variation?

A) It is uncontrollable.

B) It is centered on a mean.

C) It occurs with a somewhat consistent amount of dispersion.

D) It results from a shift in a process mean or some unexpected occurrence.

E) It results in a process that is repeatable.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

12) Process ________ means that the variation we observe in the process is random variation and not nonrandom variation.

A) optimization

B) capability

C) control

D) variability

E) stability

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

13) Process stability means that the variation we observe in the process is ________ variation.

A) abnormal

B) specific

C) random

D) systematic

E) nonrandom

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

14) To ensure that processes are stable, data are gathered in ________.

A) batches

B) networks

C) samples

D) lots

E) sets

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

15) Which of the following is not one of the alternative names for one hundred percent samples?

A) screening samples

B) sorting samples

C) rectifying samples

D) detailing samples

E) stabilizing samples

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

16) ________ is useful because it ensures independence among observations.

A) Process capability

B) Optimization

C) Population distribution

D) Process stability

E) Randomization

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

17) To ________ means to sample in such a way that every piece of product has an equal chance of being selected for inspection.

A) randomize

B) optimize

C) stabilize

D) rectify

E) modify

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

18) Samples can be ________ according to time or according to sequence.

A) random

B) uncontrollable

C) indefinite

D) systematic

E) stochastic

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

19) A ________ subgroup is a group of data that is logically homogeneous.

A) primary

B) rational

C) process

D) variable

E) stable

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

20) Variation within the data in a ________ subgroup can provide a yardstick for computing limits on the standard variation between subgroups.

A) process

B) variable

C) primary

D) stable

E) rational

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

21) ________ are tools for monitoring process variation.

A) Pareto charts

B) Control charts

C) Histograms

D) Scatter diagrams

E) Cause-and-effect diagrams

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

22) A(n) ________ is a continuous measurement such as weight, height, or volume.

A) variable

B) attribute

C) paradigm

D) criterion

E) element

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

23) A(n) ________ is an either-or-situation resulting from a binomial process.

A) variable

B) paradigm

C) criterion

D) attribute

E) element

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

24) Which of the following is an example of a variables chart?

A) u chart

B) c chart

C) np chart

D) p chart

E) X chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

25) Which of the following is an example of an attributes chart?

A) s chart

B) R chart

C) p chart

D) MR chart

E) X chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

26) What is the first step in developing process control charts?

A) identify critical product characteristics

B) select the appropriate process control chart

C) determine whether the critical product characteristic is a variable or an attribute

D) identify critical operations in the process

E) establish the control limits

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

27) Process population average, mean, range, moving range, and standard deviation are examples of ________.

A) attributes

B) variables

C) elements

D) criteria

E) paradigms

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

28) Proportion defective, number defective, number nonconforming in a consistent sample space, and number defects per unit are examples of ________.

A) criteria

B) paradigms

C) elements

D) variables

E) attributes

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

29) The ________ is a process chart used to monitor the average of the characteristic being measured.

A)  chart

B) R chart

C) c chart

D) p chart

E) MR chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

30) The ________ chart is used in monitoring process dispersion.

A)  chart

B) c chart

C) p chart

D) R chart

E) X chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

31) The  chart is a process chart used to monitor the ________ of the characteristic being measured.

A) range

B) average

C) mode

D) median

E) standard deviation

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

32) The ________ is the difference between the largest measurement and the smallest measurement in a particular sample.

A) range

B) median

C) mode

D) standard deviation

E) mean

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

33) What is the lower limit of R for sample sizes less than or equal to six?

A) -1

B) 6

C) 0

D) -6

E) 1

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

34) In a variables control chart, which of the following is likely to occur if two points in succession are farther than two standard deviations from the mean?

A) erratic behavior

B) nonrandom event

C) process drift

D) natural variation

E) process run

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

35) In a variables control chart, which of the following is likely to occur if five points are in succession, either all above or below the center line?

A) erratic behavior

B) nonrandom event

C) process drift

D) natural variation

E) process run

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

36) In a variables control chart, which of the following is likely to occur if seven points, either increasing or decreasing, are in succession?

A) erratic behavior

B) nonrandom event

C) process drift

D) natural variation

E) process run

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

37) In a variables control chart, which of the following is likely to occur if large jumps of more than three or four standard deviations take place?

A) erratic behavior

B) nonrandom event

C) process drift

D) natural variation

E) process run

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

38) A ________ is used when data are geometrically distributed.

A) p chart

B) u chart

C) c chart

D) h chart

E) g chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

39) A(n) ________ is used when data are hypergeometrically distributed.

A) p chart

B) u chart

C) c chart

D) h chart

E) g chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

40) The ________ reflects a population distribution.

A) p chart

B) s chart

C) u chart

D) X chart

E) R chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

41) Although  charts generally are preferred for variables data, sometimes it is too time consuming or inconvenient to compute subgroup averages. In these cases, a(n) ________ is used.

A)  chart

B) X chart

C) p chart

D) s chart

E) R chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

42) The ________ is often used where variation in a process is small.

A) s chart

B) X chart

C) np chart

D) u chart

E) c chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

43) ________ are often used in monitoring the production of silicon chips for computers.

A) X charts

B) c charts

C) np charts

D) R charts

E) s charts

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

44) The ________ is used for monitoring variables and measurement on a continuous scale.

A) cusum chart

B) c chart

C) X chart

D) np chart

E) moving average chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

45) The ________ uses past information to predict what the next process outcome will be.

A) np chart

B) u chart

C) moving average chart

D) cusum chart

E) p chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

46) The ________ is used to identify slight but sustained shifts in a universe where there is no independence between observations.

A) cusum chart

B) moving average chart

C) s chart

D) np chart

E) R chart

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

Use the following table to answer the question(s) below.

47) A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the center line be for a chart that monitors process dispersion?

A) 0.50

B) 0.55

C) 0.60

D) 0.69

E) 0.80

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

48) A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the center line be for a chart that monitors process average?

A) 4.58

B) 4.66

C) 4.73

D) 4.78

E) 4.82

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

49) A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the lower and upper control limits be for an X-bar chart?

A) (5.00, 8.00)

B) (-1.50, 1.50)

C) (4.33, 5.12)

D) (0.00, 1.45)

E) (-5.10, 5.10)

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

50) A machine shop owner wishes to monitor the diameter of an engine boring operation where the piston bore should be 4.25". He obtains 8 samples of 5 and records the data in the table above. What should the upper and lower control limits be for an R chart?

A) (5.00, 8.00)

B) (0.00, 2.50)

C) (4.33, 5.12)

D) (0.00, 1.45)

E) (-5.10, 5.10)

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

Use the following table to answer the question(s) below.

51) Close tolerances are required in the manufacturing section of an automotive parts business. Since the customers demand quality, the owner wants to monitor the operation closely using statistical process control. After taking 8 samples of size 4, the owner records the data in the table above. What are the lower and upper limits for a chart that will monitor process dispersion?

A) (0.00, 1.85)

B) (0.00, 2.11)

C) (0.00, 2.28)

D) (0.00, 1.03)

E) (0.00, 1.45)

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

52) Close tolerances are required in the manufacturing section of an automotive parts business. Since the customers demand quality, the owner wants to monitor the operation closely using statistical process control. After taking 8 samples of size 4, the owner finds himself with the data in the table above. What are the lower and upper limits for a chart that will monitor process average?

A) (99.68, 100.36)

B) (99.56, 100.21)

C) (99.41, 100.59)

D) (99.38, 100.82)

E) (99.99, 100.01)

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

53) Close tolerances are required in the manufacturing section of an automotive parts business. Since the customers demand quality, the owner wants to monitor the operation closely using statistical process control. After taking 8 samples of size 4, the owner finds himself with the data in the table above. What is the center line for a chart that will monitor process dispersion?

A) 0.45

B) 0.30

C) 0.00

D) 0.75

E) cannot be determined from the information given

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

54) Close tolerances are required in the manufacturing section of an automotive parts business. Since the customers demand quality, the owner wants to monitor the operation closely using statistical process control. After taking 8 samples of size 4, the owner finds himself with the data in the table above. What is the center line for a chart that will monitor process average?

A) 100.20

B) 102.00

C) 99.88

D) 98.00

E) cannot be determined from the information given

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

55) ________ refers to the ability of a process to produce a product that meets specifications.

A) Process stability

B) Process attribute

C) Process variability

D) Process capability

E) Process conformance

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

56) World-class levels of process capability are measured by ________ defect levels.

A) parts per million

B) parts per hundred thousand

C) parts per ten thousand

D) parts per thousand

E) parts per hundred

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

57) The diameter of a mason jar is 3 inches but can be as large as 3.03 inches and as small as 2.97 inches. Twenty-five samples of mason jars are taken and it is discovered that these components have a grand mean of 3.01 inches and a standard deviation of 0.02 inches. What is the probability of producing a bad product?

A) 0.60

B) 0.18

C) 0.32

D) 0.45

E) 0.84

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

58) A 50 volt battery must be between 55 and 45 volts when it leaves the factory. Two hundred samples of batteries have yielded the following data: average charge of 49 volts with a standard deviation of 2.5 volts. What is the process capability?

A) 0.06

B) 0.80

C) 0.53

D) 0.12

E) 0.38

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

59) A 50 volt battery must be between 55 and 45 volts when it leaves the factory. Two hundred samples of batteries have yielded the following data: average charge of 49 volts with a standard deviation of 2.5 volts. What is the probability of producing an out-of-spec battery?

A) 0.06

B) 0.80

C) 0.53

D) 0.12

E) 0.32

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

60) The diameter of a mason jar is 3 inches but can be as large as 3.03 inches and as small as 2.97 inches. Twenty five samples of mason jars are taken and it is discovered that these components have a grand mean of 3.01 inches and a standard deviation of 0.02 inches. What is the capability of this process?

A) 0.08

B) 0.16

C) 0.33

D) 0.49

E) 0.66

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

61) The upper and lower specifications for metal head plates are 50.1 cm. A sample of the metal head plates in 25 undergraduates yields a mean of 5.05. We know that the population standard deviation is 0.04. What is the population capability index?

A) 2.15

B) 2.51

C) 1.25

D) 1.52

E) 0.42

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

62) The upper and lower specifications for metal head plates are 50.1 cm. A sample of the metal head plates in 25 undergraduates yields a mean of 5.05. What is the population standard deviation if the population capability index is 1.666?

A) 0.01

B) 0.02

C) 0.03

D) 0.04

E) 0.05

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

63) Statistical thinking is a decision-making skill demonstrated by the ability to draw conclusions based on data.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

64) Statistical thinking is based on the concept that understanding variation and increasing variation are important keys to success.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

65) Statistical tools are deemed to fail because people have a poor understanding of the scientific method.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

66) Statistical tools focus on causes rather than effects.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

67) In the study of quality, Type I error is called consumer's risk.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

68) Producer's risk is the probability that a nonconforming product will be available for sale.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

69) Consumer's risk happens when statistical quality analysis fails to result in the scrapping or reworking of a defective product.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

70) Nonrandom variation is centered on a mean and occurs with a consistent amount of dispersion.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

71) Random variation is also referred to as uncontrollable variation.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

72) Random variation results from an event such as a shift in a process mean or some unexpected occurrence.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

73) Nonrandom variation results in a process that is not repeatable.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

74) Process stability means that the variation observed in the process is nonrandom variation and not random variation.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

75) Process charts are graphs designed to signal process workers when nonrandom variation is occurring in a process.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

76) One hundred percent samples are also known as screening samples.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

77) If a systematic sample is performed according to sequence, the product is inspected at regular intervals of time.

Answer:

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

78) Statistical process control charts are tools for monitoring process variation.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

79) An attribute is a continuous measurement such as weight, height, or volume.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

80) X chart is an example of a variables chart.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

81) The first step in developing process control charts is to identify critical product characteristics.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

82) The central limit theorem states that when we plot the sample means, the sampling distribution approximates a normal distribution.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

83) The R chart is a process chart used to monitor the average of the characteristic being measured.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

84) The lower limit of R is zero for sample sizes less than or equal to six.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

85) In a variables control chart, five points in succession are called a process run.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

86) In a variables control chart, large jumps of more than three or four standard deviations result in process drift.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

87) A g chart is useful when data are hypergeometrically distributed.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

88) X chart limits are control limits and not natural limits.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

89) If it is too time consuming or inconvenient to compute subgroup averages, a median chart should be used.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

90) The s chart is often used where variation in a process is large.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

91) The cusum chart is used for monitoring variables and measurement on a continuous scale.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

92) The moving average chart uses past information to predict what the next process outcome will be.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

93) Control chart limits should be updated only when there is a change to the process.

Answer:

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

94) Process stability refers to the ability of a process to produce a product that meets specification.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

95) World-class levels of process capability are measured by parts per million defect levels.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

96) Quality practitioners should not compare process chart limits with product specifications.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

97) Processes that achieve capability indexes of 1.25 are world-class capable.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

98) A process is capable if only common variation is present in the process.

Answer:

Topic:  Process Capability for Variables

Learning Outcome:  Apply basic statistical process control (SPC) methods

99) Interlinking is useful in helping to identify causal relationships between variables.

Answer:

Topic:  Other Statistical Techniques in Quality Management

Learning Outcome:  Apply basic statistical process control (SPC) methods

100) What is the difference between random and nonrandom variation?

Answer:  Random variation is centered on a mean and occurs with a somewhat consistent amount of dispersion. This type of variation cannot be controlled. Hence, we refer to it as "uncontrolled variation." Nonrandom or "special cause" variation results from some event. The event may be a shift in a process mean or some unexpected occurrence.

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

101) Explain why random samples are difficult to achieve in a production environment.

Answer:  In a process industry, multiple products are made by the same machines, workers, and processes in sequence. In this case, there is no statistical independence among observations because the process results in ordered products that can be subject to machine drift (going out of adjustment slowly over time).

Topic:  Statistical Fundamentals

Learning Outcome:  Apply basic statistical process control (SPC) methods

102) What is the difference between a variable and an attribute?

Answer:  variable is a continuous measurement such as weight, height, or volume. In contrast, an attribute is an either-or situation. Examples of attributes include: The motor is either starting or not starting, or either the lens is scratched or it is not.

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

103) What are the steps used in developing process control charts?

Answer:  Statistical process control charts (also referred to as process charts or control charts) are tools for monitoring process variation. Following are the steps used in developing process control charts:

•     Identify critical operations in the process where inspection might be needed.

•     Identify critical product characteristics.

•     Determine whether the critical product characteristic is a variable or an attribute.

•     Select the appropriate process control chart from among the many types of control charts.

•     Establish the control limits and use the chart to continually monitor and improve.

•     Update the limits when changes have been made to the process.

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

104) Design a control chart to monitor the gas mileage in your car. Collect the data over time.

Answer:  The control chart would include an x-bar chart and an r-chart. A sample would be recorded every time you bought gas. The samples would be correlated, not independent. The student should comment on this.

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods

105) Describe the purpose of an s chart.

Answer:  The s chart or standard deviation chart is often used where variation in a process is small. For example, s charts are often used in monitoring the production of silicon chips for computers.

Topic:  Process Control Charts

Learning Outcome:  Apply basic statistical process control (SPC) methods