Deck 3: Statistical Process Control

Question 1

After special cause variation is detected, the focus changes to identifying the root cause of the variation and eliminating it.

Answer 1

True

Question 2

Unique or special cause variation reflects the random variation associated with the output of a process.

Answer 2

False

Question 3

Process control charts are rarely useful for monitoring and controlling the output of service processes.

Answer 3

False

Question 4

A variable measure classifies while an attribute measure quantifies.

Question 5

One goal of statistical process control is to prevent a process from producing items that have to be scrapped or reworked.

Question 6

When a control chart detects no special cause (nonrandom) variation in a process, the upper and lower control limits are the same value.

Question 7

Employee training in statistical process control is a fundamental principle in total quality management programs.

Question 8

A process that is determined to be in control contains no variation.

Question 9

With a c-chart, the sample size is small and may contain only one item.

Question 10

Statistical process control is only effective for service processes.

Question 11

It is sometimes not necessary to determine new control limits after special cause (nonrandom) variation has been identified if the source has been eliminated without changing the process.

Question 12

Statistical process control is based on a philosophy of inspection as opposed to prevention.

Question 13

Statistical process control is a subset of statistical quality control.

Question 14

Statistical process control involves monitoring and controlling a process to prevent poor quality.

Question 15

Statistical process control is a tool used to monitor and improve quality.

Question 16

One reason some companies fail in their attempt to apply statistical process control is lack of training.

Question 17

Control limits are based on the special cause (nonrandom) variation inherent in a process.

Question 18

Process control is achieved by taking periodic samples from a process and plotting the sample points on a chart to determine if the process is within control limits.

Question 19

Common cause (random) variation provides evidence that the process is not in control.

Question 20

Two types of variation associated with the output of a process are common (random) cause (random) and special cause (nonrandom).

Question 21

An x-bar and R-chart constructed to monitor and control a process use the same raw data.

Question 22

Variable control charts are used for quantitative measures such as weight or time.

Question 23

Attribute control charts are used to monitor descriptive characteristics of the output of a process rather than measurable characteristics.

Question 24

The range measures the variation within samples versus the variation between samples.

Question 25

The range is the difference between the smallest and largest values in a sample.

Question 26

When a control chart detects no special cause (nonrandom) variation in a process, the upper and lower control limits are the same value.

Question 27

Variable control charts are used to monitor measurable characteristics of a process's outputs rather than descriptive characteristics.

Question 28

One advantage of using a pattern test is that special cause variations may be identified before any points are plotted outside the control limits.

Question 29

A p-chart is used to monitor the proportion defective in the output of a process.

Question 30

Control charts are never implemented until special cause variation has been detected in a process.

Question 31

It is possible to have low variation within samples while at the same time having high variation between sample means.

Question 32

The formula used to determine the upper and lower control limits are based on product specification limits.

Question 33

When calculating control limits for a process, the number of standard deviations (Z value) is typically six.

Question 34

Process control is achieved by taking periodic samples from a process and plotting the sample points on a chart to determine if the process is within control limits.

Question 35

A quantitative variable measure classifies while an qualitative variable (attribute) measure esq.uantifies.

Question 36

The individual that detects special cause variation in a process is not allowed to diagnose the root cause and correct it.

Question 37

It is sometimes not necessary to determine new control limits after special cause (nonrandom) variation has been identified if the source has been eliminated without changing the process.

Question 38

A pattern test can identify an out-of-control process even if all sample points are within control limits.

Question 39

When special cause variation is detected it is normally eliminated by increasing the number of standard deviations (Z value) used to calculate the control limits.

Question 40

A control chart is in control when the plot of the sample points exhibits a pattern.

Question 41

Control charts visually show when a process is not within statistical control limits.

Question 42

The popularity of Excel and other data analysis software has been a major factor in the increased use of statistical process control.

Question 43

When constructing a control chart for the first time, all points should be within the control limits indicating the process is in control.

Question 44

Process control charts are often used at a critical point after which it is difficult to correct or rework the process output.

Question 45

Control charts visually show when a process is not within statistical control limits.

Question 46

Defect and defective mean the same thing for attribute (qualitative) control charts.

Question 47

Special cause variation can be identified using statistical process control.

Question 48

If the points plotted on a control chart display a pattern, it is called a run.

Question 49

A process capability ratio greater than one shows that a process is capable of producing output within its specification limits.

Question 50

For a given process, the process capability ratio is not related to its specification limits.

Question 51

All processes contain a certain amount of variation in their output.

Question 52

When constructing a control chart for the first time, all points should be within the control limits indicating the process is in control.

Question 53

Process control charts are often used at a critical point after which it is difficult to correct or rework the process output.

Question 54

The process capability index indicates how much a process mean differs from the target specification value.

Question 55

A sequence of sample points that display a pattern is known as a run.

Question 56

The smaller the historical proportion defective reported for a process, the larger the sample size required to detect special cause (nonrandom) variation with a p-chart.

Question 57

Tolerances reflect the amount of common cause variation allowed in a process.

Question 58

All processes contain a certain amount of variation in their output.

Question 59

Tolerances or specification limits are allowable variation prescribed in a product design.

Question 60

Statistical process control can prevent poor quality before it occurs if a pattern is evident in the plotted points.

Question 61

It is possible to have low variation within samples while at the same time having high variation between sample means.

Question 62

The range measures the variation within samples versus the variation between samples.

Question 63

With a c-chart, the sample size is small and often may only contains only one item.

Question 64

A control chart is in control when the plot of the sample points exhibits a pattern.

Question 65

Variable (quantitative) control charts are used to monitor measurable characteristics of a process's outputs rather than descriptive characteristics.

Question 66

Variable control charts are used for quantitative measures such as weight or time.

Question 67

Statistical process control can prevent poor quality before it occurs if a pattern is evident in the plotted points.

Question 68

The process centerline for both xbar and R charts are both the same value because they are based on the same raw data.

Question 69

If the points plotted on a control chart display a pattern, it is called a run.

Question 70

An R-chart monitors the robustness of a process.

Question 71

A sequence of sample points that display a pattern is known as a run.

Question 72

One advantage of using a pattern test is that special cause variations may be identified before any points are plotted outside the control limits.

Question 73

A c-chart monitors the number of defects in small samples.

Question 74

An x-bar and R-chart constructed to monitor and control a process use the same raw data.

Question 75

If a pattern is evident in the points plotted on a control chart, the points are always considered evidence that the process is in control.

Question 76

A pattern test can identify an out-of-control process even if all sample points are within control limits.

Question 77

A p-chart is used to monitor the proportion defective in the output of a process.

Question 78

The R-chart is used for monitoring and controlling variation within samples.

Question 79

The range is the difference between the smallest and largest values in a sample.

Question 80

Attribute (qualitative) control charts are used to monitor descriptive characteristics of the output of a process rather than measurable characteristics.