Question 1

c-charts

Accepted Answer

A) Are used for the fraction of non-conforming items 
B) Count the number of nonconformances per unit 
C) Use continuous metrics 
D) Can have negative lower limits 
A) Are used for the fraction of non-conforming items 
B) Count the number of nonconformances per unit 
C) Use continuous metrics 
D) Can have negative lower limits

Question 2

A Procter 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 } \
\hline1 & 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}$$ 
a.Compute the limits for both an R chart and x-bar chart. Compare the sample results to the limits of the charts.
b.Briefly explain what the quality control charts tell you. What actions, if any, would you take?

Accepted Answer

a.UCL_R = (2.004)(.305) = 0.611 LCL_R =( 0)(

Question 3

Jim is a quality control manager at a clothing manufacturer. He is studying a quality problem where zippers are purchased from an outside supplier and have been discovered to be poorly constructed. When the zipper is manufactured correctly, it should have a mean length of 15 inches and a range of .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 =( D₂)(R-bar)

Question 4

In developing process control charts, if special causes are present, they are not representative of true state of statistical control, and the calculations of the center line and control limits will be biased.

Accepted Answer

A) True 
 B)False

Question 5

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

Accepted Answer

A) True 
 B)False

Question 6

Find the control limits for a c chart with $\bar { C }$ = 7.

Accepted Answer

LCL = 7 - 3 sq. root of (7) =

Question 7

A supplier is producing a machined part for the transmission of your vehicle. The upper specification limit is 0.125 cm and the lower specification limit is 0.085. The process standard deviation for the process that makes this part is 0.008 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 8

p-charts

Accepted Answer

A) Are used for the fraction of non-conforming items 
B) Count the number of nonconformances per unit 
C) Use continuous metrics 
D) Can have negative lower limits 
A) Are used for the fraction of non-conforming items 
B) Count the number of nonconformances per unit 
C) Use continuous metrics 
D) Can have negative lower limits

Question 9

The center line p-bar) for a p-chart is 0.50 with an UCL = 0.70 and a LCL = 0.35. The results of the next eight sample means are 0.45, 0.60, 0.39, 0.44, 0.48, 0.53, 0.54, and 0.61. What would you do?

Accepted Answer

A) Nothing; the process is in control. 
B) increase the sample size to get a better measure. 
C) investigate assignable causes because four observations are above the center line. 
D) investigate assignable causes because there is a bad trend run). 
A) Nothing; the process is in control. 
B) increase the sample size to get a better measure. 
C) investigate assignable causes because four observations are above the center line. 
D) investigate assignable causes because there is a bad trend run).

Question 10

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 .540 mm and a lower limit of .480 mm. The process has a standard deviation of .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 = UTL - LTL)/[(6)(Std. Dev. of proc

Question 11

Describe the steps required to develop and use control charts.

Accepted Answer

1.Preparation
2.Data collection
3.Determ

Question 12

Define "quality at the source."

Accepted Answer

Quality at the source means that the peo

Question 13

In manufacturing, quality control is generally applied at the receiving stage from suppliers, during various production processes, and at the finished goods stage.

Accepted Answer

A) True 
 B)False

Question 14

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 15

To account for the process centering, a two-sided capability index is often used.

Accepted Answer

A) True 
 B)False

Question 16

In general, discuss how to interpret control charts.

Accepted Answer

A process is in control when the control

Question 17

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

Accepted Answer

A) True 
 B)False

Question 18

Which one of the following statements is true?

Accepted Answer

A) Common cause variation arises from external sources that are not inherent in the process and is where statistical quality control methods are most useful. 
B) If the metric is discrete, a p- or c-chart is normally used. 
C) Statistical process control is not used in hospitals due to the high liability costs. 
D) Statistical process control charts are used when trying to monitor and control 5- and 6-sigma quality levels. 
A) Common cause variation arises from external sources that are not inherent in the process and is where statistical quality control methods are most useful. 
B) If the metric is discrete, a p- or c-chart is normally used. 
C) Statistical process control is not used in hospitals due to the high liability costs. 
D) Statistical process control charts are used when trying to monitor and control 5- and 6-sigma quality levels.

Question 19

Which of the following is most closely related to Statistical Process Control (SPC)?

Accepted Answer

A) Removing common causes of variation 
B) Removing special causes of variation 
C) Removing all causes of variation 
D) Computing process capability 
A) Removing common causes of variation 
B) Removing special causes of variation 
C) Removing all causes of variation 
D) Computing process capability

Question 20

A process is considered to be in control when all common and special causes have been eliminated.

Accepted Answer

A) True 
 B)False

c-charts

In developing process control charts, if special causes are present, they are not representative of true state of statistical control, and the calculations of the center line and control limits will be biased.

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

Find the control limits for a c chart with $\bar { C }$ = 7.

p-charts

The center line p-bar) for a p-chart is 0.50 with an UCL = 0.70 and a LCL = 0.35. The results of the next eight sample means are 0.45, 0.60, 0.39, 0.44, 0.48, 0.53, 0.54, and 0.61. What would you do?

Describe the steps required to develop and use control charts.

Define "quality at the source."

In manufacturing, quality control is generally applied at the receiving stage from suppliers, during various production processes, and at the finished goods stage.

Quality at the source means that quality is controlled by

To account for the process centering, a two-sided capability index is often used.

In general, discuss how to interpret control charts.

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

Which one of the following statements is true?

Which of the following is most closely related to Statistical Process Control (SPC)?

A process is considered to be in control when all common and special causes have been eliminated.

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 Design

Supply Chain Design

Capacity Management

Forecasting and Demand Planning

Managing Inventories

Resource Management

Operations Scheduling and Sequencing

Quality Management

Lean Operating Systems

Project Management

Work Measurement, Learning Curves, and Standards

Queuing Analysis

Modeling Using Linear Programming

Simulation

Work Measurement, Learning Curves, and Standards

Filters

Exam 16: Quality Control and Spc

c-charts

In developing process control charts, if special causes are present, they are not representative of true state of statistical control, and the calculations of the center line and control limits will be biased.

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

Find the control limits for a c chart with Cˉ\bar { C }Cˉ = 7.

p-charts

The center line p-bar) for a p-chart is 0.50 with an UCL = 0.70 and a LCL = 0.35. The results of the next eight sample means are 0.45, 0.60, 0.39, 0.44, 0.48, 0.53, 0.54, and 0.61. What would you do?

Describe the steps required to develop and use control charts.

Define "quality at the source."

In manufacturing, quality control is generally applied at the receiving stage from suppliers, during various production processes, and at the finished goods stage.

Quality at the source means that quality is controlled by

To account for the process centering, a two-sided capability index is often used.

In general, discuss how to interpret control charts.

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

Which one of the following statements is true?

Which of the following is most closely related to Statistical Process Control (SPC)?

A process is considered to be in control when all common and special causes have been eliminated.

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 Design

Supply Chain Design

Capacity Management

Forecasting and Demand Planning

Managing Inventories

Resource Management

Operations Scheduling and Sequencing

Quality Management

Lean Operating Systems

Project Management

Work Measurement, Learning Curves, and Standards

Queuing Analysis

Modeling Using Linear Programming

Simulation

Work Measurement, Learning Curves, and Standards

Filters

Find the control limits for a c chart with $\bar { C }$ = 7.