Question 1

Robust product design is a design concept that aims to reduce variation without eliminating it altogether. The following are sources of variation EXCEPT:

Accepted Answer

Unit to department is not a source of variation in robust product design.
Key Takeaway: Robust product design aims to reduce variation in a process without eliminating it. Sources of internal variation can be due to wear and tear of equipment or aging/expiration of materials used. External variation can be due to environmental conditions such as humidity or parasitic infestation. Unit to unit variation can be due to differences in machines and processes.

Question 2

The following are components of Porter's five forces EXCEPT:

Accepted Answer

Threat of complementary products is not a component of Porter's five forces.
Key Takeaway: Porter's five forces is a business strategy framework that allows organizations to analyze those threats and potentials in a new market. The goal of using this framework is to uncover such factors as the bargaining power of suppliers and customers as well as the presence of competition to determine whether the organization should promote its products in the market.

Question 3

Which one of the following is an inventive methodology for problem-solving?

Accepted Answer

TRIZ is an inventive methodology for problem-solving.
Key Takeaway: TRIZ is an inventive methodology and tool used in problem-solving. TRIZ uses failure analysis such as the reasons for an explosion in a food plant to problem-solve in the future. This methodology also uses systems' analysis whereby systems and processes are studied in depth in order to find innovative solutions to problems.

Question 4

Workers in the overnight shift at an assembly line, on average, require 8.5 minutes to complete once production cycle. Production managers have contributed this to biological differences in overnight reaction times. What type of variation is this an example of?

Accepted Answer

Inherent variation is process variation that exists naturally.
Key Takeaway: Process variations that exist naturally include nocturnal differences in human performance. If workers in the overnight shift consistently require a longer period of time to complete one production cycle, regardless of skills, staffing and machine performance, then this is considered to be inherent variation.

Question 5

The following are examples of statistical process control charts EXCEPT:

Accepted Answer

P-charts, C-charts, and Xbar charts are all examples of statistical process control charts.
Key Takeaway: A P-chart is used to illustrate proportions while a C-chart is used when counting the number of nonconformities in an area of opportunity. Xbar charts are used measuring numeric data such as means.

Question 6

In an Interrelationship Digraph, a(n) _______ and ______ relationship between two variables is depicted visually.

Accepted Answer

In an Interrelationship Digraph, a cause and effect relationship between two variables is depicted visually.
Key Takeaway: Interrelationship Digraphs are simple visual representations that show the cause and effect relationship between two or more variables. This type of representation is important in helping team members understand how different project variables interact with one another and their possible outcomes. For example, a delay in the processing of client complaints in customer service would affect technicians who are tasked with addressing these concerns.

Question 7

The Define phase is the first phase of Six Sigma's DMAIC cycle. If this phase is not planned for and carried out thoroughly, a project may stall and not transition to other phases successfully. Which of the following project statements is well-defined?

Accepted Answer

"Reduce the reject rate of service B from 30% to 10% within 2 calendar years" is a well-defined project statement.
Key Takeaway: Well-defined project statements are important in that they present a concrete goal that that has a time limit and a measurable outcome. In this example, a period of 2 years provides a guideline for employees to plan their activities to reach this goal while the percentage reduction of 20 is a measurable goal.

Question 8

A Black Belt practitioner constructs a control chart to display a process mean and its outer limits. In the chart above, what does LCL stand for?

Accepted Answer

LCL stands for Lower Control Limit
Key Takeaway: Lower Control Limits (LCL) are calculated as three standard deviations below the mean of a process. For example, if a single production cycle takes an average of 53 minutes, an LCL can be calculated using this mean and standard deviation. An LCL is useful in setting limits to product quality so that they continue to fulfill client requirements despite variations around the mean of the process.

Question 9

Which of the following areas (A or B) represents a range of special, unexpected variation?

Accepted Answer

B represents a range of special, unexpected variation.
Key Takeaway: Unlike common variation, special variation is unexpected and not inherent to the process that is to be controlled. For example, if a production cycle with a consistently narrow variation produces half of its regular outputs, then a special variation has occurred. Typically, when special variation is measures, the data points fall above or below the Upper Control Limit and the Lower Control Limit which are 3 standard deviations each from the mean.

Question 10

A Six Sigma team is asked to calculate the Return on Investment (ROI) on a new training project to be implemented across the organization. The new training project is to cost $600,000 over a period of 3 years and would involve 120 employees. The income from the project, including revenues and money saved, will be approximately $1.2 million in that same period. What is the ROI of this project?

Accepted Answer

The ROI of this project is 100. The solution is as follows:
ROI = [(Financial value ? Project cost) / Project cost] × 100
ROI = [(1,200,000 ? 600,000) / 600,000] × 100
ROI = [600,000 / 600,000] × 100
ROI = 1 × 100
ROI = 100
Key Takeaway: Return on Investment (ROI) takes into account both the cost and income of a project as a ratio. It is not the same as the revenue, which is a simple income minus cost calculation. The cost of a project is all the funds that are necessary to develop and implement it, while its income is the money gained and/or saved.

Quiz 1: Black Belt