Question 1

The purpose of a control chart is to eliminate common cause variation.

Accepted Answer

The purpose of a control chart is not to eliminate common cause variation but rather to monitor the process and identify when there is a special cause variation that needs to be addressed. The goal is to identify and eliminate the special causes of variation, which are the sources of non-random variation in the process. Common cause variation, on the other hand, is inherent in the process and cannot be eliminated but can be reduced through process improvement efforts.

Question 2

Which of the following is NOT part of the Shewhart-Deming cycle?
A) Plan
B) Act
C) Do
D) React

Accepted Answer

The correct sequence is Plan, Do, Check, Act (PDCA) or Plan, Study, Do, Act (PSDA). "React" is not a part of the cycle.

Question 3

Special or assignable causes of variation are signalled by individual fluctuations or patterns in the data.

Accepted Answer

Special or assignable causes of variation are typically marked by individual fluctuations or patterns in the data that are distinct from the common or random causes of variation. These causes may include specific events or factors that affect the process being measured, such as equipment breakdowns or changes in environmental conditions. By identifying and addressing these assignable causes, a process can be improved and made more consistent over time.

Question 4

Maintaining the gains that have been made with a revised process in the long term by avoiding potential problems that can occur when a process is changed involves which part of the DMAIC process?
A) Define
B) Measure
C) Analyse
D) Improve
E) Control

Accepted Answer

The Control phase of the DMAIC process focuses on ensuring that the improvements made during the Improve phase are sustained in the long term. This involves putting in place appropriate controls and monitoring mechanisms to avoid potential problems that can occur when the process is changed. Therefore, the best choice is E (Control).

Question 5

Common causes of variation are correctable without modifying the system.

Accepted Answer

Common causes of variation are inherent in the system and require changes to the system itself to be corrected, unlike special causes that can often be corrected without systemic changes.

Question 6

Common causes of variation represent variation due to the inherent variability in the system.

Accepted Answer

Common causes of variation are random and inherent to the system. They cannot be easily eliminated and can be attributed to factors such as differences in equipment, machines, materials or operators.

Question 7

Changes in the system to reduce common cause variation are the responsibility of management.

Accepted Answer

Common cause variation is inherent in the system and cannot be eliminated completely. However, management is responsible for implementing process improvements to minimize common cause variation and achieve stable processes.

Question 8

Which of the following is NOT one of Deming's 14 points?
A) Create constancy of purpose for improvement of product or service
B) Belief in mass inspection
C) Drive out fear
D) Adopt and institute leadership

Accepted Answer

Deming's 14 points are a set of management principles focused on improving overall quality and productivity. One of the points is to eliminate reliance on mass inspection, as Deming believed that it was not an effective way to improve quality and instead advocated for building quality into the products and processes themselves. Therefore, choice B is not one of Deming's 14 points.

Question 9

In Australia,control limits on a control chart are placed so that they are three standard deviations above and below a central line.

Accepted Answer

This is a common practice in statistical process control and is known as the "3-sigma rule." By placing the control limits at three standard deviations above and below the central line, it is expected that only 0.27% of the data points will fall outside these limits if the process is in control. This provides a way to quickly identify when the process may be out of control and needs further investigation or intervention.

Question 10

Developing operational definitions for each critical-to-quality characteristic involves which part of the DMAIC process?
A) Define
B) Measure
C) Analyse
D) Improve
E) Control

Accepted Answer

Developing operational definitions for each critical-to-quality characteristic is part of the "Measure" phase of the DMAIC process, where data is collected and analyzed to understand the baseline performance of the process.

Question 11

Which of the following is NOT part of the DMAIC process in Six Sigma management?
A) Do
B) Analyse
C) Control
D) Define

Accepted Answer

The answer of Which of the following is NOT part...

Question 12

The control chart  _______.
A) focuses on the time dimension of a system
B) can be used for categorical, discrete, or continuous variables
C) captures the natural variability in the system
D) All of the above.

Accepted Answer

The answer of The control chart  _______.
A) focuses on...

Question 13

Instruction 18-1
Below is the number of defective items from a production line over 20 consecutive morning shifts.
 $$\begin{array} { | l | l | l | l |} 
\hline \text { Day } & \text { Nonconf. } & \text { Day } & \text { Nonconf. } \
\hline 1 & 26 & 11 & 22 \
\hline 2 & 27 & 12 & 26 \
\hline 3 & 23 & 13 & 21 \
\hline 4 & 21 & 14 & 22 \
\hline 5 & 26 & 15 & 19 \
\hline 6 & 20 & 16 & 17 \
\hline 7 & 35 & 17 & 21 \
\hline 8 & 30 & 18 & 18 \
\hline 9 & 21 & 19 & 16 \
\hline 10 & 25 & 20 & 17\
\hline
\end{array}$$ Note: Nonconf. = Nonconformances
-Referring to Instruction 18-1,based on the c chart,it appears that the process is out of control.

Accepted Answer

The c chart is used to monitor the count of nonconformities per unit. If the number of nonconformities varies significantly from shift to shift, it indicates that the process is out of control. In this case, the chart shows a wide variation in the number of defects, suggesting that the process is not stable and needs to be investigated. Therefore, the answer is A, true.

Question 14

Instruction 18-1
Below is the number of defective items from a production line over 20 consecutive morning shifts.
 $$\begin{array} { | l | l | l | l |} 
\hline \text { Day } & \text { Nonconf. } & \text { Day } & \text { Nonconf. } \
\hline 1 & 26 & 11 & 22 \
\hline 2 & 27 & 12 & 26 \
\hline 3 & 23 & 13 & 21 \
\hline 4 & 21 & 14 & 22 \
\hline 5 & 26 & 15 & 19 \
\hline 6 & 20 & 16 & 17 \
\hline 7 & 35 & 17 & 21 \
\hline 8 & 30 & 18 & 18 \
\hline 9 & 21 & 19 & 16 \
\hline 10 & 25 & 20 & 17\
\hline
\end{array}$$ Note: Nonconf. = Nonconformances
-Referring to Instruction 18-1,based on the c chart,no opportunity appears to be present to render an improvement in the process.

Accepted Answer

A c-chart is used for monitoring the number of defects in a process over time. The data provided shows variability in the number of nonconformances (defects) across the 20 days, suggesting that there may be opportunities to investigate the causes of this variability and implement process improvements to reduce the number of defects.

Question 15

Instruction 18-1
Below is the number of defective items from a production line over 20 consecutive morning shifts.
 $$\begin{array} { | l | l | l | l |} 
\hline \text { Day } & \text { Nonconf. } & \text { Day } & \text { Nonconf. } \
\hline 1 & 26 & 11 & 22 \
\hline 2 & 27 & 12 & 26 \
\hline 3 & 23 & 13 & 21 \
\hline 4 & 21 & 14 & 22 \
\hline 5 & 26 & 15 & 19 \
\hline 6 & 20 & 16 & 17 \
\hline 7 & 35 & 17 & 21 \
\hline 8 & 30 & 18 & 18 \
\hline 9 & 21 & 19 & 16 \
\hline 10 & 25 & 20 & 17\
\hline
\end{array}$$ Note: Nonconf. = Nonconformances
-Referring to Instruction 18-1,based on the c chart,there appears to be a special cause of variation in the process.

Accepted Answer

The c chart is used to monitor the number of nonconformances (defects) in a process, and it assumes a stable process with only common causes of variation. If there is a special cause of variation present, it will show up as a point outside the control limits or a pattern in the data. Without seeing the actual chart, we cannot say for certain, but based on the statement that "there appears to be a special cause of variation in the process," we can infer that there is evidence of a special cause, which would make the answer A true.

Question 16

Which famous statistician developed the 14 points of management?
A) Chebyshev
B) Taguchi
C) Shewhart
D) Deming

Accepted Answer

The famous statistician who developed the 14 points of management is W. Edwards Deming.

Question 17

Determining the root causes of why defects can occur along with the variables in the process that cause these defects to occur involves which part of the DMAIC process?
A) Define
B) Measure
C) Analyse
D) Improve
E) Control

Accepted Answer

The Analyse phase of the DMAIC process involves identifying the root causes of defects and understanding the variables in the process that are contributing to these defects.

Question 18

The Shewhart-Deming cycle plays an important role in which of the following 14 points for management?
A) Eliminate slogans, exhortation, and targets for the workforce.
B) Break down barriers between staff areas.
C) Create constancy of purpose for improvement of product and services.
D) Adopt the new philosophy.

Accepted Answer

The Shewhart-Deming cycle, also known as the PDCA cycle (Plan-Do-Check-Act), is closely related to creating a constancy of purpose for the improvement of products and services. This cycle emphasizes continuous improvement, which aligns with the principle of maintaining a consistent focus on enhancing quality and service.

Question 19

The control limits are based on the standard deviation of the process.

Accepted Answer

The control limits are calculated using a multiple of the standard deviation, typically 3 or 6. Therefore, the standard deviation is a key factor in determining the control limits.

Question 20

Which of the following is NOT one of Deming's 14 points?
A) Break down barriers between staff areas
B) Drive out fear
C) Create constancy of purpose for improvement of product or service
D) Award business on the basis of price tag alone

Accepted Answer

Deming's 14 points emphasize the importance of quality, continuous improvement, and employee involvement. Awarding business solely on the basis of price tag goes against these principles.

Quiz 18: Statistical Applications in Quality Management

The purpose of a control chart is to eliminate common cause variation.

Which of the following is NOT part of the Shewhart-Deming cycle?

Special or assignable causes of variation are signalled by individual fluctuations or patterns in the data.

Maintaining the gains that have been made with a revised process in the long term by avoiding potential problems that can occur when a process is changed involves which part of the DMAIC process?

Common causes of variation are correctable without modifying the system.

Common causes of variation represent variation due to the inherent variability in the system.

Changes in the system to reduce common cause variation are the responsibility of management.

Which of the following is NOT one of Deming's 14 points?

In Australia,control limits on a control chart are placed so that they are three standard deviations above and below a central line.

Developing operational definitions for each critical-to-quality characteristic involves which part of the DMAIC process?

Which of the following is NOT part of the DMAIC process in Six Sigma management?

The control chart _______.

Which famous statistician developed the 14 points of management?

Determining the root causes of why defects can occur along with the variables in the process that cause these defects to occur involves which part of the DMAIC process?

The Shewhart-Deming cycle plays an important role in which of the following 14 points for management?

The control limits are based on the standard deviation of the process.

Which of the following is NOT one of Deming's 14 points?