Question 1

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

Accepted Answer

A) True 
 B)False

Question 2

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

Accepted Answer

A) True 
 B)False

Question 3

A c-chart is used for:

Accepted Answer

A)  means. 
B)  ranges. 
C)  percent defective. 
D)  fraction defective per unit. 
E)  number of defects per unit. 
A)  means. 
B)  ranges. 
C)  percent defective. 
D)  fraction defective per unit. 
E)  number of defects per unit.

Question 4

Consider the following information: $$\begin{array} { | l | c | c | c | c | c | c | } 
\hline \text { Observations } & 1 & 2 & 3 & 4 & 5 & 6 \
\hline \text { Num. of defects } & 10 & 18 & 13 & 15 & 9 & 12 \
\hline
\end{array}$$
The number of runs up and down for the preceding data is:

Accepted Answer

A)  3. 
B)  4. 
C)  5. 
D)  6. 
E)  none of these. 
A)  3. 
B)  4. 
C)  5. 
D)  6. 
E)  none of these.

Question 5

Control limits are based on multiples of the process standard deviation.

Accepted Answer

A) True 
 B)False

Question 6

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each: $$\begin{array} { l l c c c } 
\text { Day } & &{ \text { Weight (ounces) } } \
\hline \text { Monday } & 23 & 22 & 23 & 24 \
\text { Tuesday } & 23 & 21 & 19 & 21 \
\text { Wednesday } & 20 & 19 & 20 & 21 \
\text { Thursday } & 18 & 19 & 20 & 19 \
\text { Friday } & 18 & 20 & 22 & 20
\end{array}$$
If he uses upper and lower control limits of 22 and 18 ounces, what is his risk (alpha) of concluding this process is out of control when it is actually in control (Type I error)?

Accepted Answer

A)  0.0026 
B)  0.0456 
C)  0.3174 
D)  0.6826 
E)  0.9544 
A)  0.0026 
B)  0.0456 
C)  0.3174 
D)  0.6826 
E)  0.9544

Question 7

Range charts and p-charts are both used for variable data.

Accepted Answer

A) True 
 B)False

Question 8

If a process is performing as it should, it is still possible to obtain observations which are outside of which limits?
(I) tolerances
(II) control limits
(III) process variability

Accepted Answer

A)  I 
B)  II 
C)  I and II 
D)  II and III 
E)  I, II, and III 
A)  I 
B)  II 
C)  I and II 
D)  II and III 
E)  I, II, and III

Question 9

The purpose of control charts is to:

Accepted Answer

A)  estimate the proportion of output that is acceptable. 
B)  weed out defective items. 
C)  determine if the output is within tolerances/specifications. 
D)  distinguish between random variation and assignable variation in the process. 
E)  provide meaningful work for quality inspectors. 
A)  estimate the proportion of output that is acceptable. 
B)  weed out defective items. 
C)  determine if the output is within tolerances/specifications. 
D)  distinguish between random variation and assignable variation in the process. 
E)  provide meaningful work for quality inspectors.

Question 10

A c-chart is used to monitor the number of defects per unit for process output.

Accepted Answer

A) True 
 B)False

Question 11

Cpk is useful even when the process is not centered.

Accepted Answer

A) True 
 B)False

Question 12

An x-bar control chart can only be valid if the underlying population it measures is a normal distribution.

Accepted Answer

A) True 
 B)False

Question 13

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results: $$\begin{array} { c c c c c } 
\text { Machine } && { \text { Measurements } } \
\hline \# 1 & 17 & 15 & 15 & 17 \
\# 2 & 16 & 25 & 18 & 25 \
\# 3 & 23 & 24 & 23 & 22
\end{array}$$
What is the sample mean for machine #1?

Accepted Answer

A)  15 
B)  16 
C)  17 
D)  21 
E)  23 
A)  15 
B)  16 
C)  17 
D)  21 
E)  23

Question 14

A shift in the process mean for a measured characteristic would most likely be detected by a:

Accepted Answer

A)  p-chart. 
B)  x-bar chart. 
C)  c-chart. 
D)  R-chart. 
E)  s-chart. 
A)  p-chart. 
B)  x-bar chart. 
C)  c-chart. 
D)  R-chart. 
E)  s-chart.

Question 15

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 16

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 in 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 estimate of the standard deviation of the sampling distribution for an instructor's sample proportion of failures?

Accepted Answer

A)  .0075 
B)  .03 
C)  .075 
D)  .3 
E)  .75 
A)  .0075 
B)  .03 
C)  .075 
D)  .3 
E)  .75

Question 17

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 18

Statistical process control focuses on the acceptability of process output.

Accepted Answer

A) True 
 B)False

Question 19

Cpk can be used only when the process is centered.

Accepted Answer

A) True 
 B)False

Question 20

Run tests are useful in helping to identify nonrandom variations in a process.

Accepted Answer

A) True 
 B)False

Exam 14: Quality Control

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

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

A c-chart is used for:

Consider the following information: Observations 1 2 3 4 5 6 Num. of defects 10 18 13 15 9 12 The number of runs up and down for the preceding data is:

Control limits are based on multiples of the process standard deviation.

Range charts and p-charts are both used for variable data.

If a process is performing as it should, it is still possible to obtain observations which are outside of which limits? (I) tolerances (II) control limits (III) process variability

The purpose of control charts is to:

A c-chart is used to monitor the number of defects per unit for process output.

Cpk is useful even when the process is not centered.

An x-bar control chart can only be valid if the underlying population it measures is a normal distribution.

A shift in the process mean for a measured characteristic would most likely be detected by a:

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

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

Statistical process control focuses on the acceptability of process output.

Cpk can be used only when the process is centered.

Run tests are useful in helping to identify nonrandom variations in a process.

Introduction to Operations Management

Competitiveness

Forecasting

Product and Service Design

RELIABILITY – Static

Strategic Capacity Planning for Products and Services

Decision Theory– Static

Process Selection and Facility Layout

Work Design and Measurement

learning curve– Static

Location Planning and Analysis

The Transportation Model– Static

Management of Quality

Acceptance Sampling– Static

Aggregate Planning and Master Scheduling

MRP and ERP

Inventory Management

JIT and Lean Operations

Maintenance– Static

Supply Chain Management

Scheduling

Project Management

Management of Waiting Lines

Linear Programming

Filters