Deck 17: Quality Management

Question 1

Statistical process control charts (SPC charts) are attributed to Shewhart.

Answer 1

True

Question 2

ISO 9000 specifies quality processes rather than defect rates.

Answer 2

True

Question 3

The development of acceptance sampling is attributed to the works of Taguchi and Ishikawa.

Answer 3

False

Question 4

An important attribute of quality is conformance to specifications.

Question 5

Control charts are used to monitor the quality of a product before it is produced.

Question 6

The Japanese invented and implemented quality control techniques prior to World War II.

Question 7

Pareto charts show the frequency of problems that affect a process in descending order.

Question 8

An in-control process will always exhibit some common cause variation.

Question 9

The C_pk index may indicate a capable process even though the C_p index is unacceptable.

Question 10

Process control charts were adopted by the Japanese after World War II.

Question 11

ISO 9000 standards were first developed in the United States under the leadership of Joseph Juran.

Question 12

Special cause variation exists when the process produces observations that are not from the same population as the majority of the observations.

Question 13

A p-chart is a type of process control chart that can be used for plotting the proportion of nonconforming sampled items.

Question 14

A major goal in statistical quality control is the reduction of variation in a process.

Question 15

A moving range (MR) chart is appropriate to monitor variation when every single item is being inspected (n = 1) since the range (R) cannot be calculated.

Question 16

Quality control refers to methods used by organizations to ensure that their products and services meet customer expectations.

Question 17

If a single sample mean is 2.1 standard deviations above the centerline, the process is not in control.

Question 18

A process may be in a state of control even if one sample mean is more than two standard deviations above the centerline.

Question 19

Common cause variation does not indicate an out-of-control process.

Question 20

The presence of common cause variation is an indication that the process is out of control.

Question 21

The upper and lower control limits of an $\overline { X ^ { * } }$ chart are typically set at plus or minus three standard errors from the centerline.

Question 22

If USL = 550, LSL = 540, μ = 545, and σ = 1.00, the C_p index is 1.67.

Question 23

Management wants a process to be in control and have a capability index at least equal to 1.33 (and ideally much more than 1.33).

Question 24

The C_p index equals the C_pk index if USL = 550, LSL = 540, μ = 543, and σ = 0.75.

Question 25

Deming thought that the majority of quality problems were traceable to faulty equipment.

Question 26

If you increase the size of the samples taken when using an $\overline { X ^ { * } }$ chart, it is necessary to recalculate your control limits because the limits will be wider.

Question 27

In general terms, a capable process is one whose variability (σ) is small in relation to the distance between the centerline μ and the upper and lower specification limits.

Question 28

As a rule of thumb, if a process C_pk index is less than 1.00, the level of process capability is usually judged acceptable.

Question 29

If USL = 550, LSL = 540, μ = 545, and σ = 1.75, the process is highly capable.

Question 30

Deming stressed identifying the workers who contributed the most to poor quality.

Question 31

Quality management is characterized by focus on the customer and continual improvement.

Question 32

The C_p index equals the C_pk index if USL = 550, LSL = 540, μ = 545, and σ = 0.75.

Question 33

If USL = 550, LSL = 540, μ = 545, and σ = 0.4, the process is highly capable.

Question 34

In statistical process control, the C_pk index measures the separate distances between the centerline μ and the USL and LSL.

Question 35

A p-chart is a type of process control chart that is used for plotting the number of defects per unit produced.

Question 36

Fishbone diagrams were developed for the Japanese fishing industry.

Question 37

If you increase the size of the samples taken when using an $\overline { X ^ { * } }$ chart, it is necessary to recalculate your control limits because the limits will be narrower.

Question 38

A process whose output distribution is stable over time is said to be in statistical control, regardless of whether the desired specifications are being met.

Question 39

The C_p index equals the C_pk index if USL = 550, LSL = 540, μ = 546, and σ = 1.25.

Question 40

A c-chart is based on the Poisson distribution.

Question 41

Which is not a true statement about the life and philosophy of W. Edwards Deming?

A)He taught quality control techniques to Japanese companies during the 1950s.
B)He lived a very long life and was a highly paid consultant past age 80.
C)He invented control charts and proposed the ISO 9000 standard.
D)He believed that poor quality is not primarily the fault of the workers.

Question 42

The problem that is probably the hardest to identify from a control chart is:

A)mixture.
B)oscillation.
C)cycle.
D)trend.

Question 43

Which is an appropriate step in continuous quality improvement?

A)Taking measurements on a variable and keeping careful records
B)Posting quality banners or company flags where they are visible to all
C)Castigating the lazy employees for their shoddy workmanship
D)Sending employees to Motivation Camp taught by expensive consultants

Question 44

Which is not a tool of statistical quality control?

A)Fishbone diagram
B)Pareto chart
C)Attribute control chart
D)Deming chart

Question 45

Control charts were an innovation attributed to:

A)Deming in the 1950s.
B)Shewhart in the 1920s.
C)Westinghouse in the 1960s.
D)Pacioli in the 1490s.

Question 46

__________ and ___________ are well known for their statistical work related to customer satisfaction and the cost of quality.

A)Deming ; Shewhart
B)Harold; Kumar
C)Dodge; Romig
D)Taguchi; Ishikawa

Question 47

Quality is ultimately best assessed by:

A)trained statisticians.
B)quality control inspectors.
C)management.
D)customers.

Question 48

Attribute control charts would not be used to display the:

A)proportion of nonconforming parts.
B)sample range for a measured variable.
C)total number of nonconforming parts.
D)average number of nonconforming parts.

Question 49

Which of the following is not a characteristic of Total Quality Management?

A)Employee empowerment
B)Reduction of waste
C)Continuous improvement
D)Reducing the C_p index

Question 50

Which of the following is most likely the cause of a level shift in a SPC chart?

A)Tool wear
B)A new worker
C)Temperature fluctuations
D)Alternating samples from two machines

Question 51

The R chart is likely to reveal which problem?

A)Instability
B)Cycles
C)Level shift
D)Trend

Question 52

The development of acceptance sampling is attributed to the works of:

A)Deming and Shewhart.
B)Potter and Granger.
C)Dodge and Romig.
D) Taguchi and Ishikawa.
E) Harold
F) Dodge and Harry

Question 53

Walter Shewhart was an American who studied the control charts that the Japanese had invented after World War II and brought those methods back to the United States during the 1980s.

Question 54

A control chart for the mean tells whether the product conforms to specifications.

Question 55

Likely reasons for inaccurate control limits would include which of the following?

A)The engineering parameter for variance is unknown.
B)The engineers were underpaid for their work.
C)There was insufficient preliminary sampling.
D)Process variation was not zero, as expected.

Question 56

Control charts (SPC charts) are attributed to:

A)Deming.
B)Shewhart.
C)Juran.
D)Taguchi.

Question 57

Instability is most readily apparent on the:

A) $\overline { X ^ { * } }$ chart.
B)R chart.
C)np chart.
D)I chart.

Question 58

Quality experts would probably not recommend:

A)reducing variation.
B)using control charts.
C)placing blame for poor work.
D)identifying sources of variation.

Question 59

Instability in a process is indicated when samples:

A)tend to alternate between high and low values.
B)drift slowly either upward or downward.
C)vary more than expected.
D)shift abruptly either above or below the centerline.

Question 60

In statistical process control, control charts are used to ensure that a process is stable and in control by detecting special cause variation.

Question 61

Ten samples of n = 5 were collected to construct an $\overline { x ^ { * } }$ chart. The sample mean and range for each sample are shown in the table below. $$\begin{array} { | c c c | c c c | } \hline \text { Sample } & \text { Mean } & \text { Range } & \text { Sample } & \text { Mean } & \text { Range } \\\hline 1 & 215 & 15 & 6 & 224 & 21 \\2 & 204 & 20 & 7 & 205 & 27 \\3 & 160 & 10 & 8 & 184 & 12 \\4 & 226 & 19 & 9 & 207 & 16 \\5 & 232 & 24 & 10 & 212 & 17 \\\hline\end{array}$$ Calculate the empirical centerline for the $\overline { x ^ { * } }$ chart.

A)210.5
B)206.9
C)205.3
D)208.2

Question 62

Find the C_pk index for a process with USL = 550, LSL = 540, μ = 543, and σ = 0.75.

A)1.33
B)2.22
C)1.25
D)1.75

Question 63

Statistical process control charts can measure:

A)the stability of the process.
B)the capability of a process.
C)both stability and capability.

Question 64

Find the C_pk index for a process with USL = 550, LSL = 540, μ = 544, and σ = 1.25.

A)1.33
B)2.22
C)1.07
D)1.75

Question 65

Find the C_p index for a process with USL = 550, LSL = 540, μ = 543, and σ = 0.75.

A)1.25
B)1.33
C)2.22
D)1.75

Question 66

A slow drift of measurements either up or down from the process centerline suggests a:

A)mixed process.
B)trend.
C)instability.
D)cycle.

Question 67

Refer to the diagram below: For this process, the C_p index would be:

A)less than one.
B)equal to one.
C)greater than one.

Question 68

Which is not a characteristic of a p-chart?

A)It shows the number of defects per item being inspected.
B)It measures the fraction of nonconforming items in a sample.
C)It is based on the binomial distribution (or its normal approximation).
D)It will have varying control limits if the sample size is changing.

Question 69

A level shift in a process is indicated when samples:

A)tend to alternate between high and low values.
B)drift slowly either upward or downward.
C)vary more than expected.
D)shift abruptly to a new mean.

Question 70

Find the C_pk index for a process with USL = 550, LSL = 540, μ = 545, and σ = 0.75.

A)1.33
B)2.22
C)1.25
D)1.75

Question 71

Ten samples of n = 5 were collected to construct an $\overline { x ^ { * } }$ chart. The sample mean and range for each sample are shown in the table below. $$\begin{array} { | c c c | c c c | } \hline \text { Sample } & \text { Mean } & \text { Range } & \text { Sample } & \text { Mean } & \text { Range } \\\hline 1 & 215 & 15 & 6 & 224 & 21 \\2 & 204 & 20 & 7 & 205 & 27 \\3 & 160 & 10 & 8 & 184 & 12 \\4 & 226 & 19 & 9 & 207 & 16 \\5 & 232 & 24 & 10 & 212 & 17 \\\hline\end{array}$$ Calculate the empirical lower and upper control limits for the $\overline { x ^ { * } }$ chart. (You will need a table of control chart factors.) $$\begin{array} { c l l r } \hline \text { Subgroup Size } & d _ { 2 } & D _ { 3 } & D _ { 4 } \\\hline 2 & 1.128 & 0 & 3.267 \\3 & 1.693 & 0 & 2.574 \\4 & 2.059 & 0 & 2.282 \\5 & 2.326 & 0 & 2.114 \\6 & 2.534 & 0 & 2.004 \\7 & 2.704 & 0.076 & 1.924 \\8 & 2.847 & 0.136 & 1.864 \\9 & 2.970 & 0.184 & 1.816 \\\hline\end{array}$$

A)196.46, 217.34
B)171.81, 241.39
C)188.03, 225.17
D)163.64, 250.56

Question 72

Ten samples of n = 5 were collected to construct an $\overline { x ^ { * } }$ chart. The sample mean and range for each sample are shown in the table below. $$\begin{array} { | c c c | c c c | } \hline \text { Sample } & \text { Mean } & \text { Range } & \text { Sample } & \text { Mean } & \text { Range } \\\hline 1 & 215 & 15 & 6 & 224 & 21 \\2 & 204 & 20 & 7 & 205 & 27 \\3 & 160 & 10 & 8 & 184 & 12 \\4 & 226 & 19 & 9 & 207 & 16 \\5 & 232 & 24 & 10 & 212 & 17 \\\hline\end{array}$$ Calculate the empirical centerline for the R chart.

A)20.8
B)17.2
C)18.1
D)19.4

Question 73

Which statistician developed the 14 Points of Quality?

A)Juran
B)Deming
C)Taguchi
D)Ishikawa

Question 74

Which is not a rule of thumb to indicate an out-of-control process on the $\overline { X ^ { * } }$ chart?

A)Single point outside three sigma
B)Three of four successive points outside two sigma on the same side of the centerline
C)Four of five successive points outside one sigma on the same side of the centerline
D)Nine successive points on the same side of the centerline

Question 75

In manufacturing, if workers readjust the equipment after each sample, it would typically:

A)increase variation.
B)decrease variation.
C)widen the specification limits.
D)improve conformance to specifications.

Question 76

Find the C_p index for a process with USL = 550, LSL = 540, μ = 545, and σ = 0.75.

A)1.25
B)1.33
C)2.22
D)1.75

Question 77

Is a process capable if USL = 550, LSL = 540, μ = 542, and σ = 1.25?

A)No, clearly not
B)No, but very close
C)Yes, just barely
D)Yes, highly capable

Question 78

Which is not a characteristic of instability?

A)Larger than normal amount of variation
B)Higher-than-expected frequencies in tails of the distribution of means
C)Often caused by untrained operators
D)Specification limits that are too narrow

Question 79

If the specification subgroup size is n = 4 and the known process parameters are ? = 2.75 and ? = .044, the control limits for the $\bar { X }$ chart will be:

A)LCL = 2.684, UCL = 2.816.
B)LCL = 2.728, UCL = 2.772.
C)LCL = 2.618, UCL = 2.882.
D)LCL = 2.518, UCL = 2.998.

Question 80

Which is not characteristic of a trend?

A)Variance is essentially unchanged from sample to sample.
B)It is often due to mixing two batches of materials.
C)It is detectable on a control chart if enough samples are taken.
D)Rules of thumb can be established to detect it.