Deck 17: Process Improvement Using Control Charts

Question 1

Sigma level capability is the number of estimated process standard deviations between the estimated process mean and the specification limit closest to the estimated process mean.

Answer 1

True

Question 2

How well the design of the product meets and exceeds the needs and expectations of the customers is called the quality of performance.

Answer 2

False

Question 3

Periodic sampling is observing the output of a process at random intervals.

Answer 3

False

Question 4

A cause-and-effect diagram enumerates the potential causes of an undesirable effect on the process to discover sources of process variation and to identify opportunities for process improvement.

Question 5

A range chart is a control chart on which ranges between individual process measurements within a subgroup are plotted.

Question 6

A sequence of steadily decreasing points on a control chart is called run down.

Question 7

A p chart is a control chart on which the proportions of nonconforming units are plotted versus time.

Question 8

When using $\bar { X }$
and R charts to analyze and improve a process,first,the $\bar { X }$
chart is analyzed and the necessary action(s)to correct assignable causes of variation is (are)taken before the R chart is analyzed.

Question 9

If a manufacturing process is in statistical control,it means that the process is capable of producing products that meets the customer's needs.

Question 10

Reducing common causes of variation usually requires action by management.

Question 11

A control chart is a graph whose purpose is to detect assignable causes of variation in a process.

Question 12

Process leeway is the distance between natural tolerance limits and control limits.

Question 13

How well a process is able to meet the requirements set forth by the process design is called the quality of design.

Question 14

If a process is stable and in statistical control,it is not influenced by assignable causes of variation.

Question 15

For a given control chart,zone boundaries consist of the UCL and LCL.

Question 16

An $\bar { X }$
chart is a control chart on which individual process measurements are plotted versus time.

Question 17

A goal of statistical process control is continuous process improvement.

Question 18

If a process is only influenced by common causes of variation,we can state that the process is in statistical control.

Question 19

Control charts are used to reduce common causes of variation.

Question 20

Unusual sources of variation that can be attributed to specific causes are called the common causes of process variation.

Question 21

Common causes of process variation:

A)Are sources of unusual process variation.
B)Usually must be remedied by management.
C)Usually must be remedied by local supervision.
D)Always exist together with assignable causes of variation.
E)Can never be remedied or reduced.

Question 22

How well a product or service performs in the marketplace is called:

A)Process capability.
B)Quality of conformance.
C)Quality of performance.
D)Quality of design.
E)Process control.

Question 23

Rational subgrouping allows us to detect changes ____________ subgroups.

A)Within
B)Between
C)In the sizes of
D)None of these

Question 24

When employing measurement data to study a process,the __________ monitors the process variation.

A) $\overline { \mathcal { X } }$
Chart
B)R chart
C)p chart
D)Natural tolerance
E)Pattern analysis

Question 25

Observing the output of a process at fixed time intervals is referred to as ___________ sampling.

A)Consecutive
B)Random
C)Fixed
D)Periodic

Question 26

When employing measurement data to study a process,the ____________ monitors the process mean.

A) $\overline { \mathcal { X } }$
Chart
B)p-bar chart
C)R chart
D)Natural tolerance
E)Pattern analysis

Question 27

When a process is influenced only by common causes of variation:

A)The process may also be influenced by assignable causes of variation.
B)Many plot points on a control chart will be outside the control limits.
C)The process is always capable of meeting customer requirements.
D)The process is in statistical control.
E)The process is never capable of meeting customer requirements.

Question 28

If a control chart is used correctly,and the necessary corrective actions are taken,as the control limits get ____________,the potential quality of the product _____________.

A)Looser,increases
B)Tighter,decreases
C)Tighter,increases
D)None of these

Question 29

If the ________ limits are within the ________ limits,then it can be concluded that the process is __________.

A)Specification,natural,capable
B)Natural,specification,stable
C)Specification,natural,stable
D)Natural,specification,capable

Question 30

In a manufacturing process,if the limits for a control chart are set too _____________,the risk of unnecessarily tampering with the process ____________.

A)Tight,increases
B)Loose,increases
C)Tight,decreases
D)None of these

Question 31

A(n)_______ chart monitors the number of nonconformities units in a subgroup.

A) $\overline { \mathcal { X } }$
B)R
C)C
D)p

Question 32

How well the design of a product or service meets and exceeds the needs and expectations of the customer is called:

A)Process capability.
B)Quality of conformance.
C)Quality of performance.
D)Quality of design.
E)Process control.

Question 33

How well a process is able to meet the requirements set forth by the process design is called:

A)Process leeway.
B)Quality of conformance.
C)Quality of performance.
D)Quality of design.

Question 34

Which of the following control charts is designed to control the proportion of nonconforming units?

A)p chart
B) $\overline { \mathcal { X } }$
Chart
C)R chart

Question 35

If the process variability steadily increases,we would observe:

A)An alternating pattern of a high value followed by a low value on the R chart.
B)An upward trend on the R chart.
C)A downward trend on the R chart.
D)A increasing gradual funnel pattern on the R chart.
E)A decreasing gradual funnel pattern on the R chart.

Question 36

If a company is using an $\overline { \mathcal { X } }$
chart for a given process with measurement data,it is generally not important or necessary to use an R chart or s chart.

Question 37

In a manufacturing process,if the limits for a control chart are set too _____________,the risk of not investigating a special cause of variation and possibly not taking a corrective action ____________.

A)Tight,increases
B)Loose,increases
C)Loose,decreases
D)None of these

Question 38

Common causes of variation represent the inherent variability of a given process.

Question 39

The natural tolerance limits for a normally distributed process that is in statistical control:

A)Extend beyond the specification limits when a process is capable.
B)Are within the specification limits when a process is capable.
C)Contain approximately 99.73 percent of the individual process measurements.
D)Both Are within the specification limits when a process is capable and Contain approximately 99.73 percent of the individual process measurements are correct.
E)Both Extend beyond the specification limits when a process is capable and Contain approximately 99.73 percent of the individual process measurements are correct.

Question 40

In 25 samples of 100 units each,75 units were found to be defective.Find the appropriate UCL and LCL for the p chart.

A)0 to .0642
B)0 to .0828
C)0 to .0812
D).0129 to .0471
E)0 to .1324

Question 41

A control chart on which the proportions of nonconforming units in subgroups of size n are plotted versus time is a(n)_____ chart.

A) $\overline { \mathrm { X } }$
B)R
C)p
D)C

Question 42

The distance between natural tolerance limits and customer specifications is called ____________.

A)process leeway
B)sigma level
C)control limits
D)a zone

Question 43

A control chart on which subgroup ranges are plotted versus time is a(n)_____ chart.

A) $\overline { \mathrm { X } }$
B)R
C)p
D)C

Question 44

For a manufacturing process, $\overline { \overline X }$
= 10 inches, $\overline { \mathrm { R } }$
= )4 inches,and the subgroup sample size is 6 units.Calculate the natural tolerance limits for this process.

A)[9.526,10.474]
B)[9.510,10.490]
C)[9.484,10.516]
D)[9.807,10.193]
E)[9.769,10.231]

Question 45

A powder metal manufacturing company is producing sleeves for a locking mechanism.The target (nominal)value for the inside diameter is 1 inch.The inside diameter specifications are 1 ± .005 inches.Assume that the process is in statistical control with $\overline { \overline { X } }$

= 1)0002 inches, $\overline { \mathrm { R } }$
= )003 inches,and subgroup size of 5.Determine the estimated number of standard deviations of process leeway.

A)3
B)1.667
C)3.72
D)1.443
E).72

Question 46

A(n)____________ process has the ability to produce products or services that meet customer requirements.

A)in-control
B)assignable
C)capable
D)statistical

Question 47

A control chart on which subgroup means are plotted versus time is a(n)_________ chart.

A) $\overline { \mathrm { X } }$
B)R
C)p
D)C

Question 48

A powder metal manufacturing company is producing sleeves for a locking mechanism.The target (nominal)value for the inside diameter is 1 inch.The inside diameter specifications are 1 ± .005 inches.Assume that the process is in statistical control with $\overline { \overline { X } }$


= 1)0002 inches, $\overline { \mathrm { R } }$
= )003 inches,and subgroup size of 5.Calculate the estimated proportion of out-of-specification sleeve inside diameters.

A).0471
B).0217
C).0001
D).4783
E).0139

Question 49

A sequence of steadily increasing plot points on a control chart is referred to as ___________.

A)funneling
B)a run up
C)a cycle
D)out of control

Question 50

Sources of process variations that are inherent to the process design are called ___________ causes of variation.

A)common
B)assignable
C)unusual
D)expected

Question 51

If a control chart is used correctly and the necessary corrective actions are taken,then as the control limits get close to each other,the potential quality of the product _____________.

A)decreases
B)increases
C)stays the same
D)fluctuates

Question 52

For a manufacturing process, $\overline { \overline X }$
= 10 inches, $\overline { \mathrm { R } }$
= )4 inches,and the subgroup sample size is 6 units.Calculate the standard control limits for the R chart.

A)0 and .846
B)0 and .802
C)0 and .77
D)0 and 1.0
E)-.09 and .89

Question 53

A powder metal manufacturing company is producing sleeves for a locking mechanism.The target (nominal)value for the inside diameter is 1 inch.The inside diameter specifications are 1 ± .005 inches.Assume that the process is in statistical control with $\overline { \overline{ X } }$

= 1)0002 inches, $\overline { \mathrm { R } }$
= )003 inches,and subgroup size of 5.What are the natural tolerance limits for this process? Is the process capable?

A).99847 to 1.00193,yes
B).99847 to 1.00193,no
C).99633 to 1.004,yes
D).99633 to 1.004,no
E).995 to 1.005,yes

Question 54

A ___________ is a set of process observations that are examined for the purpose of constructing control charts.

A)Subgroup
B)Sample
C)Zone
D)List of common causes

Question 55

A powder metal manufacturing company is producing sleeves for a locking mechanism.The target (nominal)value for the inside diameter is 1 inch.The inside diameter specifications are 1 ± .005 inches.Assume that the process is in statistical control with $\overline { \overline X }$
= 1)0002 inches, $\overline { \mathrm { R } }$
= )003 inches,and subgroup size of 5.Calculate the control limits for the $\overline { X }$

Chart.

A).99781 to 1.00219
B).99801 to 1.00238
C).99830 to 1.00713
D).99847 to 1.00193
E).995 to 1.005

Question 56

___________ causes of variation may be remedied by local supervision.

A)Common
B)Assignable
C)Usual
D)Expected

Question 57

Auxiliary lines drawn on a control chart for accomplishing pattern analysis are called ___________ boundaries.

A)sigma
B)range
C)zone
D)mean

Question 58

A powder metal manufacturing company is producing sleeves for a locking mechanism.The target (nominal)value for the inside diameter is 1 inch.The inside diameter specifications are 1 ± .005 inches.Assume that the process is in statistical control with $\overline { \overline { X } }$

= 1)0002 inches, $\overline { \mathrm { R } }$
= )003 inches,and subgroup size of 5.What is the sigma level capability for this process?

A)3.0
B)3.72
C)1.6
D)1.0
E)2.72

Question 59

A systematic method for analyzing process data in which we monitor process variation is called ______________.

A)control charting
B)sigma level capability
C)statistical process control
D)rational subgrouping

Question 60

For a manufacturing process, $\overline { \overline X }$
= 10 inches, $\overline { \mathrm { R } }$
= )4 inches,and the subgroup sample size is 6 units.Calculate the standard control limits for the $\bar { X }$
Chart.

A)9.526 and 10.474
B)9.769 and 10.231
C)9.807 and 10.193
D)9.484 and 10.516
E)8.80 and 11.20

Question 61

If 20 samples of size 7 are drawn,with $\overline { \overline { X } }$

= 33.33 and $\bar { R }$
= 5)65,what are the LCL and the UCL for the $\bar { X }$
Chart?

A)[32.313,34.347]
B)[30.963,35.697]
C)[27.68,38,98]
D)[32.911,33.749]

Question 62

How well a product or a service performs in the marketplace is called the quality of ______________.

A)performance
B)conformance
C)design
D)control

Question 63

If 20 samples of size 7 are drawn,with $\overline { \overline X }$

= 33.33 and $\bar { R }$
= 5)65,what is the A-B upper boundary for the $\bar { X }$
Chart?

A)35.697
B)34.908
C)34.347
D)34.008

Question 64

If $\overline { \overline { X } }$

= 5)2, $\bar { R }$
= )3,and n = 4,calculate the natural tolerance limits.

A)[5.054,5.346]
B)[4.3,6.1]
C)[4.806,5.594]
D)[4.763,5.637]

Question 65

If $\overline { \mathrm { X } }$
And R charts are used to control a manufacturing process,an ______ chart is analyzed first and brought into a state of statistical control before preparing the _______ chart.

A)R,
$\overline { \mathrm { X } }$
B) $\overline { \mathrm { X } }$

Question 66

From 20 samples of size 100,a total of 80 units are defective.What is the centerline for the p chart?

A).04
B).4
C).8
D).08

Question 67

_________ is the set of international standards on quality management and quality assurance systems.It establishes processes for assuring that goods and services offered by the company meet a consistent level of quality acceptable to customers.

A)Control Charting
B)SQC
C)ISO 9000
D)ASQC

Question 68

Unusual sources of process variation that can be attributed to specific reasons are called ____________ causes of variation.

A)common
B)assignable
C)usual
D)expected

Question 69

If $\bar { p }$
= )0139 and 25 shipments of 20 items each were examined,what are the UCL and the LCL for the p chart?

A)[.0118,.0159]
B)[0,.0401]
C)[.008,.0198]
D)[0,.0924]

Question 70

If $\overline { \overline { X } }$

= 2)0144, $\bar { R }$
= )0972,and there are 25 subgroups of size 5,find the UCL and the LCL for the R chart.

A)[.045,.1498]
B)[.0972,.2055]
C)[0,.2055]
D)[0.2,114]

Question 71

If $\overline { \overline { X } }$

= 5)2, $\bar { R }$
= )3,and n = 4,and if the specifications are [4.6,5.8],is the process capable?

A)Yes
B)No
$$\mathrm { NTL } = 5.2 \pm 3 \left( \frac { 0.3 } { 2.059 } \right) = 4.763 \text { to } 5.637$$

Question 72

If 20 samples of size 7 are drawn,with $\overline { \overline X }$

= 33.33 and $\bar { R }$
= 5)65,what are the LCL and UCL for the R chart?

A)[2.345,8.955]
B)[.076,1.924]
C)[.415,1.585]
D)[.429,10.871]

Question 73

Assume that 25 samples of 50 each are taken and the total number of defectives is 34.Calculate $\bar { p }$
)

A).680
B).453
C).816
D).0272

Question 74

A unit that fails to meet specifications is called a _____________ unit.

A)conforming
B)capable
C)defective
D)common cause

Question 75

If $\overline { \overline { X } }$

= 16.1, $\bar { R }$
= )03,and n = 6,calculate the natural tolerance limits.

A)[16.065,16.135]
B)[16.088,16.112]
C)[15.745,16.455]
D)[16.055,16.145]

Question 76

If $\overline { \overline { X } }$

= 2)0144, $\bar { R }$
= )0972,and there are 25 subgroups of size 5,find the UCL and the LCL for the $\bar { x }$
Chart.

A)[1.999,2.029]
B)[1.958,2.071]
C)[1.917,2.112]
D)[1.437,2.591]

Question 77

The number of estimated process standard deviations between $\overline { \mathrm { X } }$
And the closest specification limit is the _____________ of the process.

A)sigma level capability
B)leeway
C)mean
D)capability

Question 78

In 20 samples,there are 80 units defective.If each sample consists of 100 units,find the appropriate UCL and the LCL for the p chart.

A)[.0269,.0531]
B)[.0204,.0596]
C)[.0380,.0420]
D)[0,.0988]

Question 79

How well a process is able to meet the requirements set forth by the process design is called the quality of _____________.

A)performance
B)conformance
C)design
D)control

Question 80

If $\overline { \overline { X } }$

= 16.1, $\bar { R }$
= )03,and n = 6,and if the specifications are [15.9,16.3],is the process capable?

A)Yes
B)No
$$\mathrm { NTL } = 16.1 \pm 3 \left( \frac { 0.03 } { 2.534 } \right) = 16.065 \text { to } 16.135$$