Question 1

The probability of a Type I error is the probability of concluding that assignable variation is present even though only random variation exists.

Accepted Answer

A) True 
 B)False

Question 2

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 under control,package weight is normally distributed with a mean of twenty ounces and a standard deviation of two ounces.Each day last week,he randomly selected four packages and weighed each with the following results:   If he uses upper and lower control limits of 23 and 17 ounces,on what day(s),if any,does this process appear to be out of control?

Accepted Answer

A) Monday 
B) Tuesday 
C) Monday and Tuesday 
D) Monday,Tuesday,and Thursday 
E) The process is in control 
A) Monday 
B) Tuesday 
C) Monday and Tuesday 
D) Monday,Tuesday,and Thursday 
E) The process is in control

Question 3

Given the following process control data for a quality attribute (three samples of size 400 each):
   If the process is known to produce 11 percent defectives on average,using three sigma control limits,do any of the sample proportions indicate an out-of-control process proportion of defectives?

Accepted Answer

No,all are

Question 4

When a process is not centred,its capability should be based on Cpk because it considers the upper and lower design specifications separately and not just the overall design specification width.

Accepted Answer

A) True 
 B)False

Question 5

When a process is judged out of control for an important character?istic,what corrective action should be taken?

Accepted Answer

A) The process should be stopped and corrective action must be taken. 
B) The process should be investigated for Type I error. 
C) The process should be investigated for Type II error. 
D) The process should continue,however,100% inspection is required. 
E) The process should continue until another sample is taken. 
A) The process should be stopped and corrective action must be taken. 
B) The process should be investigated for Type I error. 
C) The process should be investigated for Type II error. 
D) The process should continue,however,100% inspection is required. 
E) The process should continue until another sample is taken.

Question 6

A design engineer wants to construct a sample mean chart for controlling the service life of one of the types of light bulbs his company produces.He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours.On three recent production batches,he tested service life on random samples of four bulbs,with these results:   What is the standard deviation of the sampling distribution of sample means?

Accepted Answer

A) 5 hours 
B) 6.67 hours 
C) 10 hours 
D) 11.55 hours 
E) 20 hours 
A) 5 hours 
B) 6.67 hours 
C) 10 hours 
D) 11.55 hours 
E) 20 hours

Question 7

The Chair of the Operations Management Department at Quality University wants to construct a p-chart for determining whether the four instructors 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:   What is the estimate of the mean proportion of failures,(p̅)for these instructors?

Accepted Answer

A) .10 
B) .11 
C) .13 
D) .16 
E) .40 
A) .10 
B) .11 
C) .13 
D) .16 
E) .40

Question 8

A sample statistic that falls outside the control limits suggests that the process mean has changed.

Accepted Answer

A) True 
 B)False

Question 9

There is no direct link between design specifications and statistical process control limits.

Accepted Answer

A) True 
 B)False

Question 10

This involves performing experiments by changing levels of factors to measure their influence on output and identifying best levels for each factor.

Accepted Answer

A) Process capability indexes 
B) Design of experiments 
C) Six sigma quality 
D) Assignable variation influence 
E) Run tests 
A) Process capability indexes 
B) Design of experiments 
C) Six sigma quality 
D) Assignable variation influence 
E) Run tests

Question 11

Sample range control charts are used to monitor process dispersion.

Accepted Answer

A) True 
 B)False

Question 12

When using a capability index which value determines the capability of the process?

Accepted Answer

A) The smaller of the two calculations 
B) The larger of the two calculations 
C) The average of the calculations 
D) The largest minus the smallest 
E) The largest divided by the smallest 
A) The smaller of the two calculations 
B) The larger of the two calculations 
C) The average of the calculations 
D) The largest minus the smallest 
E) The largest divided by the smallest

Question 13

A design engineer wants to construct a sample mean chart for controlling the service life of one of the types of light bulbs his company produces.He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours.On three recent production batches,he tested service life on random samples of four bulbs,with these results:   If he uses upper and lower control limits of 520 and 480 hours,on what sample(s)(if any)does service life appear to be out of control?

Accepted Answer

A) Sample 1 
B) Sample 2 
C) Sample 3 
D) Both samples 2 and 3. 
A) Sample 1 
B) Sample 2 
C) Sample 3 
D) Both samples 2 and 3.

Question 14

The DMAIC methodology involves all EXCEPT which of the following?

Accepted Answer

A) Define 
B) Model 
C) Analyze 
D) Improve 
E) Control 
A) Define 
B) Model 
C) Analyze 
D) Improve 
E) Control

Question 15

A p-chart is used to monitor the fraction of defectives in the output of a process.

Accepted Answer

A) True 
 B)False

Question 16

A p-chart is used to measure shifts in process dispersion.

Accepted Answer

A) True 
 B)False

Question 17

The specifications for a product are 6 mm $\pm$0.1 mm.The process is known to operate at a mean of 6.05 mm with a standard deviation of 0.01 mm.What is the Cpk for this process?

Accepted Answer

A) 3.33 
B) 1.67 
C) 5.00 
D) 2.50 
A) 3.33 
B) 1.67 
C) 5.00 
D) 2.50

Question 18

A Quality Analyst wants to construct a control chart for determining whether four machines,all producing the same product,are under control with regard to a particular quality attribute.Accordingly,she inspected 1,000 units of output from each machine in random samples,with the following results:   What are the control chart upper and lower control limits for an alpha risk of .05?

Accepted Answer

A) .0272 and .0128 
B) .0289 and .0111 
C) .029 and .013 
D) .0303 and .0097 
E) .0332 and .0068 
A) .0272 and .0128 
B) .0289 and .0111 
C) .029 and .013 
D) .0303 and .0097 
E) .0332 and .0068

Question 19

Nonrandom variation is indicated when a point is observed that is outside the control limits,or a run test produces a large z-value.What is this a sign of?

Accepted Answer

A) Excessive random variation 
B) Assignable variation 
C) The process is in control 
D) The control limit is incorrect 
E) More samples are required. 
A) Excessive random variation 
B) Assignable variation 
C) The process is in control 
D) The control limit is incorrect 
E) More samples are required.

Question 20

Concluding that a process has changed when it has not is known as a Type II error.

Accepted Answer

A) True 
 B)False

Exam 15: Statistical Quality Control

The probability of a Type I error is the probability of concluding that assignable variation is present even though only random variation exists.

Given the following process control data for a quality attribute (three samples of size 400 each): If the process is known to produce 11 percent defectives on average,using three sigma control limits,do any of the sample proportions indicate an out-of-control process proportion of defectives?

When a process is not centred,its capability should be based on Cpk because it considers the upper and lower design specifications separately and not just the overall design specification width.

When a process is judged out of control for an important character?istic,what corrective action should be taken?

A sample statistic that falls outside the control limits suggests that the process mean has changed.

There is no direct link between design specifications and statistical process control limits.

This involves performing experiments by changing levels of factors to measure their influence on output and identifying best levels for each factor.

Sample range control charts are used to monitor process dispersion.

When using a capability index which value determines the capability of the process?

The DMAIC methodology involves all EXCEPT which of the following?

A p-chart is used to monitor the fraction of defectives in the output of a process.

A p-chart is used to measure shifts in process dispersion.

The specifications for a product are 6 mm ±\pm± 0.1 mm.The process is known to operate at a mean of 6.05 mm with a standard deviation of 0.01 mm.What is the Cpk for this process?

Nonrandom variation is indicated when a point is observed that is outside the control limits,or a run test produces a large z-value.What is this a sign of?

Concluding that a process has changed when it has not is known as a Type II error.

Introduction to Operations Management

Competitiveness, strategic Planning, and Productivity

Demand Forecasting

Product Design

Reliability

Strategic Capacity Planning

Decision Analysis

Process Design and Facility Layout

Linear Programming

Workjob Design

Learning Curves

Location Planning and Analysis

the Transportation Model

Management of Quality

Acceptance Sampling

Supply Chain Management

Inventory Management

Aggregate Operations Planning and Master Scheduling

Material Requirements Planning and Enterprise Resource Planning

Just-In-Time and Lean Production

Maintenance

Job and Staff Scheduling

Project Management

Waiting-Line Analysis

Simulation

Filters

When a process is not centred,its capability should be based on C_pk because it considers the upper and lower design specifications separately and not just the overall design specification width.

The specifications for a product are 6 mm $\pm$ 0.1 mm.The process is known to operate at a mean of 6.05 mm with a standard deviation of 0.01 mm.What is the Cpk for this process?