Question 1

The goal of statistical process control (SPC) is to help identify and eliminate unwanted causes of variation.

Accepted Answer

A) True 
 B)False

Question 2

Find the control limits for a c-chart with c-bar= 7.

Accepted Answer

LCL = 7 − 3 sq. root of (7) =

Question 3

Explain and give the significance of the 1:10:100 Rule.

Accepted Answer

If a defect or service error is identifi

Question 4

It is not necessary to have a process in control when establishing control limits.

Accepted Answer

A) True 
 B)False

Question 5

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $$z = 3$$ . Suppose a sample had 0.044 defectives. What would be the best action to take in this scenario?

Accepted Answer

A)  Nothing; it appears to be random variation. 
B)  Look for assignable causes. 
C)  Change z to 2 and take another sample. 
D)  Change z to 4 and continue sampling. 
A)  Nothing; it appears to be random variation. 
B)  Look for assignable causes. 
C)  Change z to 2 and take another sample. 
D)  Change z to 4 and continue sampling.

Question 6

Quality at the source means that quality is controlled by _____.

Accepted Answer

A)  people responsible for the work 
B)  quality control managers 
C)  front line supervisors 
D)  top management 
A)  people responsible for the work 
B)  quality control managers 
C)  front line supervisors 
D)  top management

Question 7

A c-chart is used to monitor the proportion of nonconforming units, whereas a p-chart is used to monitor the number of nonconformances per unit.

Accepted Answer

A) True 
 B)False

Question 8

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $$z = 3$$ . Suppose a sample had 0.054 defectives. What would be the best action to take in this scenario?

Accepted Answer

A)  Nothing; it appears to be random variation. 
B)  Look for assignable causes. 
C)  Change z to 2 and take another sample. 
D)  Change z to 4 and continue sampling. 
A)  Nothing; it appears to be random variation. 
B)  Look for assignable causes. 
C)  Change z to 2 and take another sample. 
D)  Change z to 4 and continue sampling.

Question 9

A p-chart _____.

Accepted Answer

A)  is used to monitor the proportion of nonconforming items 
B)  counts the number of nonconformances per unit 
C)  uses continuous metrics 
D)  can have negative lower limits 
A)  is used to monitor the proportion of nonconforming items 
B)  counts the number of nonconformances per unit 
C)  uses continuous metrics 
D)  can have negative lower limits

Question 10

The lower and upper specification limits for a component are 4.20 and 4.30 ounces, respectively. The process standard deviation is .02, and the process average is 4.24 ounces. Which one of the following statements is TRUE?

Accepted Answer

A)  The Cp index indicates the process is centered. 
B)  The Cp index indicates the process is not centered. 
C)  The Cpk index indicates the process is centered. 
D)  The Cpk index indicates the process is not centered. 
A)  The Cp index indicates the process is centered. 
B)  The Cp index indicates the process is not centered. 
C)  The Cpk index indicates the process is centered. 
D)  The Cpk index indicates the process is not centered.

Question 11

A steel company is interested in determining if a particular process in its mini-mill is capable of meeting customer expectations. The thickness of steel has an upper limit of 0.540 mm and a lower limit of 0.480 mm. The process has a standard deviation of 0.02 mm.
a.What is the process capability index (Cp) for this process?
b.What must the standard deviation of the process be changed to for the Cp to equal 1.00?

Accepted Answer

a.C_p = (USL - LSL)/6 ? = (0.540 - 0.480)/

Question 12

As long as there are no points outside of the control limits in a control chart, the process would always be considered to be in control.

Accepted Answer

A) True 
 B)False

Question 13

Quality at the source focuses on supplier quality at the beginning of a value chain.

Accepted Answer

A) True 
 B)False

Question 14

A supplier is producing a machined part for the transmission of a vehicle. The upper specification limit is 0.135 cm, and the lower specification limit is 0.075. The process standard deviation for the process that makes this part is 0.005, and the process average is 0.105. What conclusion can be drawn from these process capability data?

Accepted Answer

A) The process is centered and capable. 
B) The process is not centered and capable. 
C) The process is centered and not capable. 
D) The process is not centered and not capable. 
A) The process is centered and capable. 
B) The process is not centered and capable. 
C) The process is centered and not capable. 
D) The process is not centered and not capable.

Question 15

The value of Cpk is the average of the lower and upper capability indexes; that is, Cpk = (Cpl + Cpu)/2.

Accepted Answer

A) True 
 B)False

Question 16

A Proctor and Gamble factory process fills boxes with detergent. Construct an appropriate set of control charts to monitor the process. Historical data for fill weight (in ounces) of eight samples is presented below. A sample size of six was used.
 $\begin{array} { c c c } 
\text { Sample } & \text { Sample Mean } & \text { Sample Range } \
\hline 1 & 15.80 & 0.42 \
2 & 16.10 & 0.38 \
3 & 16.02 & 0.08 \
4 & 15.95 & 0.15 \
5 & 16.12 & 0.42 \
6 & 16.18 & 0.23 \
7 & 15.87 & 0.36 \
8 & 16.20 & 0.40
\end{array}$ Worksheet (this will not be graded but will help you answer exam questions)
    
-For the Proctor and Gamble detergent box problem, the upper control limit for the range chart is _____.

Accepted Answer

A)  less than or equal to 0.6 
B)  more than 0.6 but less than or equal to 0.7 
C)  more than 0.7 but less than or equal to 0.8 
D)  more than 0.8 
A)  less than or equal to 0.6 
B)  more than 0.6 but less than or equal to 0.7 
C)  more than 0.7 but less than or equal to 0.8 
D)  more than 0.8

Question 17

With good management, all variability of output from any goods- or service-producing process can be eliminated.

Accepted Answer

A) True 
 B)False

Question 18

The lower the rate of defects, the higher the sample size should be in p-charts.

Accepted Answer

A) True 
 B)False

Question 19

A company is measuring the time it takes to complete an order. Twenty-five samples of size 6 resulted in an average time of 80 minutes with an average range of 20 minutes. Find control limits for the appropriate control chart(s) that would be used to monitor this process.

Accepted Answer

Because the measurement is a continuous

Question 20

Jim is a quality control manager at a clothing manufacturing company. He studies a quality problem where zippers are purchased from an outside supplier. He discovers that they are poorly constructed. When the zipper is manufactured correctly, it should have a mean length of 15 inches and a range of 0.5 inches. Jamie proposes that 25 samples of five observations each should be collected on a daily basis. He plans to prepare control charts to monitor the progress of the supplier's quality performance on the zippers.
a.What are the upper and lower control limits and center line for an R-chart?
b.What are the upper and lower control limits and center line for an x-bar chart?

Accepted Answer

a.Upper limit for the R-chart = (D₄)(R-ba

The goal of statistical process control (SPC) is to help identify and eliminate unwanted causes of variation.

Find the control limits for a c-chart with c-bar= 7.

Explain and give the significance of the 1:10:100 Rule.

It is not necessary to have a process in control when establishing control limits.

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $z = 3$ . Suppose a sample had 0.044 defectives. What would be the best action to take in this scenario?

Quality at the source means that quality is controlled by _____.

A c-chart is used to monitor the proportion of nonconforming units, whereas a p-chart is used to monitor the number of nonconformances per unit.

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $z = 3$ . Suppose a sample had 0.054 defectives. What would be the best action to take in this scenario?

A p-chart _____.

The lower and upper specification limits for a component are 4.20 and 4.30 ounces, respectively. The process standard deviation is .02, and the process average is 4.24 ounces. Which one of the following statements is TRUE?

As long as there are no points outside of the control limits in a control chart, the process would always be considered to be in control.

Quality at the source focuses on supplier quality at the beginning of a value chain.

The value of C_pk is the average of the lower and upper capability indexes; that is, C_pk = (C_pl + C_pu)/2.

With good management, all variability of output from any goods- or service-producing process can be eliminated.

The lower the rate of defects, the higher the sample size should be in p-charts.

A company is measuring the time it takes to complete an order. Twenty-five samples of size 6 resulted in an average time of 80 minutes with an average range of 20 minutes. Find control limits for the appropriate control chart(s) that would be used to monitor this process.

Goods, Services, and Operations Management

Value Chains

Measuring Performance in Operations

Operations Strategy

Technology and Operations Management

Goods and Service Design

Process Selection, Design, and Analysis

Facility and Work Designs

Supply Chain Design

Capacity Management

Forecasting and Demand Planning

Managing Inventories

Resource Management

Operations Scheduling and Sequencing

Quality Management

Appendix: Quality Management

Appendix: Queuing Analysis

Appendix: Modeling Using Linear Programming

Lean Operating Systems

Appendix: Simulation

Project Management

Appendix: Decision Analysis

Filters

Exam 16: Quality Control and Spc

The goal of statistical process control (SPC) is to help identify and eliminate unwanted causes of variation.

Find the control limits for a c-chart with c-bar= 7.

Explain and give the significance of the 1:10:100 Rule.

It is not necessary to have a process in control when establishing control limits.

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using z=3z = 3z=3 . Suppose a sample had 0.044 defectives. What would be the best action to take in this scenario?

Quality at the source means that quality is controlled by _____.

A c-chart is used to monitor the proportion of nonconforming units, whereas a p-chart is used to monitor the number of nonconformances per unit.

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using z=3z = 3z=3 . Suppose a sample had 0.054 defectives. What would be the best action to take in this scenario?

A p-chart _____.

The lower and upper specification limits for a component are 4.20 and 4.30 ounces, respectively. The process standard deviation is .02, and the process average is 4.24 ounces. Which one of the following statements is TRUE?

As long as there are no points outside of the control limits in a control chart, the process would always be considered to be in control.

Quality at the source focuses on supplier quality at the beginning of a value chain.

The value of Cpk is the average of the lower and upper capability indexes; that is, Cpk = (Cpl + Cpu)/2.

With good management, all variability of output from any goods- or service-producing process can be eliminated.

The lower the rate of defects, the higher the sample size should be in p-charts.

A company is measuring the time it takes to complete an order. Twenty-five samples of size 6 resulted in an average time of 80 minutes with an average range of 20 minutes. Find control limits for the appropriate control chart(s) that would be used to monitor this process.

Goods, Services, and Operations Management

Value Chains

Measuring Performance in Operations

Operations Strategy

Technology and Operations Management

Goods and Service Design

Process Selection, Design, and Analysis

Facility and Work Designs

Supply Chain Design

Capacity Management

Forecasting and Demand Planning

Managing Inventories

Resource Management

Operations Scheduling and Sequencing

Quality Management

Appendix: Quality Management

Appendix: Queuing Analysis

Appendix: Modeling Using Linear Programming

Lean Operating Systems

Appendix: Simulation

Project Management

Appendix: Decision Analysis

Filters

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $z = 3$ . Suppose a sample had 0.044 defectives. What would be the best action to take in this scenario?

Historically, the average proportion of defective bars has been 0.015. Samples will be of 100 bars each. Construct a p-chart using $z = 3$ . Suppose a sample had 0.054 defectives. What would be the best action to take in this scenario?

The value of C_pk is the average of the lower and upper capability indexes; that is, C_pk = (C_pl + C_pu)/2.