Question 1

Common cause variation generally accounts for about 10 to 15% of all variation within a process.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following suggests a process that is not in control?

Accepted Answer

A) Points follow a smooth pattern from the lower control limit to the upper control limit 
B) The number of points above and below the center line is about the same 
C) Points fall randomly above and below the center line 
D) No points are outside the control limits 
A) Points follow a smooth pattern from the lower control limit to the upper control limit 
B) The number of points above and below the center line is about the same 
C) Points fall randomly above and below the center line 
D) No points are outside the control limits

Question 3

A production process is sampled 24 times with a sample size of 6 yields an overall mean of 25.2 and an average range of 0.8. Determine the control limits for the x-bar and R-charts.

Accepted Answer

For the x-bar-chart, A₂ = 0.483; thus the

Question 4

If no special causes affect the output of a process, we say that the process is ____; when special causes are present, the process is said to be ____.

Accepted Answer

A) Qualified; not qualified 
B) In control; out of control 
C) Capable; not capable 
D) Certified; not certified 
A) Qualified; not qualified 
B) In control; out of control 
C) Capable; not capable 
D) Certified; not certified

Question 5

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 proce

Question 6

In general, discuss how to interpret control charts.

Accepted Answer

A process is in control when the control

Question 7

Fifteen samples of size 5 have been taken from a production process. The sum of the sample averages was found to be 92.54 cm while the sum of the ranges was 115.36. Find the values of the center lines for the x-bar and R-charts.

Accepted Answer

For the x-bar chart,

Question 8

An airline found that on average, 0.62% of the luggage they received from passengers at LAX (Los Angeles Airport) is lost or damaged. On a typical day, 1000 pieces of luggage pass through this airport. What are the control limits for a p-chart for monitoring the daily fraction nonconforming?

Accepted Answer

Standard deviation of p-bar =

Question 9

A high-paced discount store in Los Angeles has noticed that checking errors have increased recently. They plan to use control charts with three standard deviation control limits to monitor the process. They decided to take a sample of 100 transactions over each of 10 days. The number of transactions in error for each day was 5, 7, 6, 5, 6, 4, 6, 3, 10, and 8.
a.What is the center line for the p-chart?
b.What is the upper control limit for the p-chart?
c.What is the lower control limit for the p-chart?

Accepted Answer

a.Center line = observed overall proport

Question 10

The time to check out guests at a hotel was measured over the course of several weeks. Management believes that the target time for checking out guests should be between 2 and 4 minutes with a target of 3 minutes. The data gathered had a mean time of 2.75 minutes with a standard deviation of 0.4 minutes. Find and interpret Cp, Cpl, Cpu, and Cpk in the context of this situation.

Accepted Answer

C_p = (UTL -LTL)/6@#LAT-DLM& = (4 - 2)/(6 * 0.4) = 0

Question 11

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 12

Flaws are counted on a standard steel plate (sheet). Each sheet has the exact same dimensions. Ten sheets are selected at random and the number of flaws per sheet is as follows:   
Determine the lower and upper control limits for a c-chart.

Accepted Answer

Calculate c-bar = 15/10 = 1.5.

Question 13

In the 1:10:100 Rule, which of the following would be correct?

Accepted Answer

A) If a defect or service error is identified and corrected at the design stage, it might cost $100 to fix. 
B) If a defect or service error is identified and corrected at the production process stage, it might cost $100 to fix. 
C) If a defect or service error is identified and corrected after it reaches the customer, it might cost $100 to fix. 
D) If a defect or service error is identified and corrected at the design stage, it might cost $1 * $10 * $100 = $1,000 to fix. 
A) If a defect or service error is identified and corrected at the design stage, it might cost $100 to fix. 
B) If a defect or service error is identified and corrected at the production process stage, it might cost $100 to fix. 
C) If a defect or service error is identified and corrected after it reaches the customer, it might cost $100 to fix. 
D) If a defect or service error is identified and corrected at the design stage, it might cost $1 * $10 * $100 = $1,000 to fix.

Question 14

To monitor the fraction of printed circuit boards that do not pass a functional test, a(n) ____ is used.

Accepted Answer

A)    -chart 
B) p-chart 
C) c-chart 
D) R-chart 
A)    -chart 
B) p-chart 
C) c-chart 
D) R-chart

Question 15

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 16

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.   
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 17

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 18

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

Accepted Answer

LCL = 7- 3 sq. root

Question 19

A bottling process sometimes results in overfills or underfills. Overfills are especially damaging to the equipment. Which process capability index would this company most want to monitor?

Accepted Answer

A) Cp 
B) Cpl 
C) Cpu 
D) Cpk 
A) Cp 
B) Cpl 
C) Cpu 
D) Cpk

Question 20

Historically, the average proportion of defective bars has been 0.015. Samples of 100 bars each are taken. Construct a p-chart using z = 3. Suppose a sample had 0.044 defectives. What would you do?

Accepted Answer

A) Nothing; it appears to be random variation. 
B) Look for assignable causes. 
C) Delete the sample with 0.044 defects and take another sample that is better. 
D) None of these choices 
A) Nothing; it appears to be random variation. 
B) Look for assignable causes. 
C) Delete the sample with 0.044 defects and take another sample that is better. 
D) None of these choices

Common cause variation generally accounts for about 10 to 15% of all variation within a process.

Which of the following suggests a process that is not in control?

A production process is sampled 24 times with a sample size of 6 yields an overall mean of 25.2 and an average range of 0.8. Determine the control limits for the x-bar and R-charts.

If no special causes affect the output of a process, we say that the process is ; when special causes are present, the process is said to be .

In general, discuss how to interpret control charts.

Fifteen samples of size 5 have been taken from a production process. The sum of the sample averages was found to be 92.54 cm while the sum of the ranges was 115.36. Find the values of the center lines for the x-bar and R-charts.

An airline found that on average, 0.62% of the luggage they received from passengers at LAX (Los Angeles Airport) is lost or damaged. On a typical day, 1000 pieces of luggage pass through this airport. What are the control limits for a p-chart for monitoring the daily fraction nonconforming?

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.

Flaws are counted on a standard steel plate (sheet). Each sheet has the exact same dimensions. Ten sheets are selected at random and the number of flaws per sheet is as follows: Determine the lower and upper control limits for a c-chart.

In the 1:10:100 Rule, which of the following would be correct?

To monitor the fraction of printed circuit boards that do not pass a functional test, a(n) ____ is used.

p-charts

c-charts

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

A bottling process sometimes results in overfills or underfills. Overfills are especially damaging to the equipment. Which process capability index would this company most want to monitor?

Historically, the average proportion of defective bars has been 0.015. Samples of 100 bars each are taken. Construct a p-chart using z = 3. Suppose a sample had 0.044 defectives. What would you do?

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

Filters

Exam 16: Quality Control and Spc

Common cause variation generally accounts for about 10 to 15% of all variation within a process.

Which of the following suggests a process that is not in control?

A production process is sampled 24 times with a sample size of 6 yields an overall mean of 25.2 and an average range of 0.8. Determine the control limits for the x-bar and R-charts.

If no special causes affect the output of a process, we say that the process is ____; when special causes are present, the process is said to be ____.

In general, discuss how to interpret control charts.

Fifteen samples of size 5 have been taken from a production process. The sum of the sample averages was found to be 92.54 cm while the sum of the ranges was 115.36. Find the values of the center lines for the x-bar and R-charts.

An airline found that on average, 0.62% of the luggage they received from passengers at LAX (Los Angeles Airport) is lost or damaged. On a typical day, 1000 pieces of luggage pass through this airport. What are the control limits for a p-chart for monitoring the daily fraction nonconforming?

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.

Flaws are counted on a standard steel plate (sheet). Each sheet has the exact same dimensions. Ten sheets are selected at random and the number of flaws per sheet is as follows: Determine the lower and upper control limits for a c-chart.

In the 1:10:100 Rule, which of the following would be correct?

To monitor the fraction of printed circuit boards that do not pass a functional test, a(n) ____ is used.

p-charts

c-charts

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

A bottling process sometimes results in overfills or underfills. Overfills are especially damaging to the equipment. Which process capability index would this company most want to monitor?

Historically, the average proportion of defective bars has been 0.015. Samples of 100 bars each are taken. Construct a p-chart using z = 3. Suppose a sample had 0.044 defectives. What would you do?

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

Filters

If no special causes affect the output of a process, we say that the process is ; when special causes are present, the process is said to be .