Question 1

If a point on a control chart falls outside one of the control limits, this suggests that the process output is nonrandom and should be investigated.

Accepted Answer

A) True 
 B)False

Question 2

Approximately 99.7 percent of sample means will fall within plus or minus two standard deviations of the process mean if the process is under control.

Accepted Answer

A) True 
 B)False

Question 3

The amount of inspection we choose can range from no inspection at all to inspecting each item numerous times.

Accepted Answer

A) True 
 B)False

Question 4

Statistical process control is the measurement of rejects in the final product.

Accepted Answer

A) True 
 B)False

Question 5

A stent for use in coronary surgery requires a special coating. Specifications for this coating call for it to be at least 0.05 millimeters but no more than 0.15 millimeters. Suppose the long-run average of this coating process is 0.09 millimeters. Further suppose this process's standard deviation is 0.015 millimeters. What proportion of the output from this process will fail to meet specifications?

Accepted Answer

The answer of A stent for use in coronary surgery...

Question 6

Perform run tests on the given data. What can you conclude? $$\begin{array} { l c } 
\text { Sample } & \text { Defectives } \
\hline 1 & 18 \
2 & 24 \
3 & 19 \
4 & 22 \
5 & 20 \
6 & 19 \
7 & 22 \
8 & 23 \
9 & 25 \
10 & 17 \
11 & 20 \
12 & 23 \
13 & 21 \
14 & 16
\end{array}$$

Accepted Answer

The expected number of above/below runs

Question 7

A lower control limit must by definition be a value less than an upper control limit.

Accepted Answer

A) True 
 B)False

Question 8

An analyst counted 17 A/B runs and 15 U/D runs in 26 time series observations. Do these results suggest that the data are non-random?

Accepted Answer

\[\begin{array} { l l l l l } 
\text { T

Question 9

A process results in a few defects occurring in each unit of output. Long-run, these defects should be monitored with:

Accepted Answer

A)  p-charts. 
B)  c-charts. 
C)  x-bar charts. 
D)  R-charts. 
E)  o-charts. 
A)  p-charts. 
B)  c-charts. 
C)  x-bar charts. 
D)  R-charts. 
E)  o-charts.

Question 10

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?

Accepted Answer

A)  mean 
B)  variance 
C)  standard deviation 
D)  range 
E)  proportion 
A)  mean 
B)  variance 
C)  standard deviation 
D)  range 
E)  proportion

Question 11

A stent for use in coronary surgery requires a special coating. Specifications for this coating call for it to be at least 0.05 millimeters but no more than 0.15 millimeters. Assuming that the process mean of 0.09 cannot be changed, what process standard deviation would be required for this process to be considered capable (assuming that a capable process must have a capability index of at least 1.3)?

Accepted Answer

The process standard deviation

Question 12

Quality control, in contrast to quality assurance, is implemented:

Accepted Answer

A)  during production. 
B)  by top management. 
C)  after production. 
D)  by self-directed teams. 
E)  before inspection. 
A)  during production. 
B)  by top management. 
C)  after production. 
D)  by self-directed teams. 
E)  before inspection.

Question 13

Given the following process control data for a quality attribute (three samples of size 400 each): $$\begin{array} { l r } 
\text { Sample } & \text { Defectives } \
\hline \# 1 & 36 \
\# 2 & 32 \
\# 3 & 52
\end{array}$$ If the process is known to produce 11 percent defectives on average, what is the alpha risk (probability of Type I error) for upper and lower control limits of .1256 and .0944 respectively? .1412 and .0788? .1568 and .0632?

Accepted Answer

The answer of Given the following process control data for...

Question 14

Concluding that a process is out of control when it is not is known as a Type I error.

Accepted Answer

A) True 
 B)False

Question 15

Control limits tend to be wider for more variable processes.

Accepted Answer

A) True 
 B)False

Question 16

The variation of a sampling distribution is tighter than the variation of the underlying process distribution.

Accepted Answer

A) True 
 B)False

Question 17

The purpose of statistical process control is to ensure that historical output is random.

Accepted Answer

A) True 
 B)False

Question 18

The process capability index (indicated by Cpk) can be used only when the process is centered.

Accepted Answer

A) True 
 B)False

Question 19

A time-ordered plot of representative sample statistics is called a(n):

Accepted Answer

A)  Gantt chart. 
B)  simo chart. 
C)  control chart. 
D)  up-down matrix. 
E)  standard deviation table. 
A)  Gantt chart. 
B)  simo chart. 
C)  control chart. 
D)  up-down matrix. 
E)  standard deviation table.

Question 20

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are under control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results: $$\begin{array} { l c } 
\text { Instructor } & \text { Number of Failures } \
\hline \text { Prof. A } & 13 \
\text { Prof. B } & 0 \
\text { Prof. C } & 11 \
\text { Prof. D } & 16
\end{array}$$ What is the sample proportion of failures (p) for Prof. D?

Accepted Answer

A)  0 
B)  .04 
C)  .11 
D)  .13 
E)  .16 
A)  0 
B)  .04 
C)  .11 
D)  .13 
E)  .16

Exam 10: Quality Control

If a point on a control chart falls outside one of the control limits, this suggests that the process output is nonrandom and should be investigated.

Approximately 99.7 percent of sample means will fall within plus or minus two standard deviations of the process mean if the process is under control.

The amount of inspection we choose can range from no inspection at all to inspecting each item numerous times.

Statistical process control is the measurement of rejects in the final product.

Perform run tests on the given data. What can you conclude? Sample Defectives 1 18 2 24 3 19 4 22 5 20 6 19 7 22 8 23 9 25 10 17 11 20 12 23 13 21 14 16

A lower control limit must by definition be a value less than an upper control limit.

An analyst counted 17 A/B runs and 15 U/D runs in 26 time series observations. Do these results suggest that the data are non-random?

A process results in a few defects occurring in each unit of output. Long-run, these defects should be monitored with:

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?

Quality control, in contrast to quality assurance, is implemented:

Concluding that a process is out of control when it is not is known as a Type I error.

Control limits tend to be wider for more variable processes.

The variation of a sampling distribution is tighter than the variation of the underlying process distribution.

The purpose of statistical process control is to ensure that historical output is random.

The process capability index (indicated by Cpk) can be used only when the process is centered.

A time-ordered plot of representative sample statistics is called a(n):

Introduction to Operations Management

Competitiveness, Strategy, and Productivity

Forecasting

Product and Service Design

Extension: Reliability

Strategic Capacity Planning for Products and Services

Extension: Decision Theory

Process Selection and Facility Layout

Work Design and Measurement

Extension: Learning Curves

Location Planning and Analysis

Extension: The Transportation Model

Management of Quality

Extension: Acceptance Sampling

Aggregate Planning and Master Scheduling

MRP and ERP

Inventory Management

Jit and Lean Operations

Extension: Maintenance

Supply Chain Management

Scheduling

Project Management

Management of Waiting Lines

Linear Programming

Filters

The process capability index (indicated by C_pk) can be used only when the process is centered.