Question

True or False

1. T F   Six Sigma relates to a 3.4 DPMO.

2. T F Six Sigma can not be applied to service companies.

3. T F   Walter Shewhart stated that, “A phenomenon is said to be in statistical control when, through the use of past experience, we can say that our product is within the specification limits.”

4. T F   Variation exists in every process.

5. T F   Potential sources of variation include methods, manpower, material, and equipment.

6. T F   The voice of the customer is usually expressed on the control chart as control limits.

7. T F   Quality begins with control and inspection.

8. T F   Product quality is determined during the manufacturing of the product.

9. T F   Most companies operate at a 3 to 4 sigma level.

10. T F   The project charter serves as contract between project team and sponsor.

11. T F   Once the project charter is develop and completed, it should not be changed in order to avoid confusion.

Answer 1

1) Six Sigma relates to a 3.4 DPMO - TRUE

Six sigma means a measure of quality that strives for near perfection. The objective of Six Sigma quality is to reduce process output variation so that on a long term basis, which is the customer’s aggregate experience with our process over time, this will result in no more than 3.4 defect parts per million (PPM) opportunities.

A Six Sigma process has a 99.99966% defect-free rate. This is equivalent to 3.4 DPMO (defects per million opportunities), or a single defect for every 294,000 units. Thus Six Sigma relates to a 3.4 DPMO.

2) Six Sigma can not be applied to service companies - FALSE

Six sigma might not apply to all service processes. With adjustments, it can apply to most service companies. Six sigma concentrates on improvement of service process inorder to improve service quality focus on service process. The wider applicability of six sigma depends on identification of key performance indicators (KPIs) for different types of service process. Standardized services, such as credit card account services or fast-food service, can yield substantial benefits from a Six Sigma process.

3) Walter Shewhart stated that, “A phenomenon is said to be in statistical control when, through the use of past experience, we can say that our product is within the specification limits”​​ - TRUE

Walter Shewhart stated that, “A phenomenon will be said to be controlled when, through the use of past experience, we can predict, at least within limits, how the phenomenon may be expected to vary in the future." Here it is understood that prediction within limits means that we can state, at least approximately, the probability that the observed phenomenon will fall within the given limits.

4) Variation exists in every process - TRUE

Variation is the enemy of quality. It can be partitioned between "common causes" and "assignable causes". Common cause variation exists in every process, it can be reduced by process improvement activities, but not eliminated. It is the variation that is inherent in a process. Assignable cause variation is unnatural variation in a process. It should be identified and addressed. Control charts enable us to determine the type of variation that exists in a process.

5) Potential sources of variation include methods, manpower, material, and equipment - TRUE

​Potential sources of variation include methods, manpower, material, machines or equipment used, measurement techniques and surrounding environment. Collectively these potential sources of variation​ are sometimes referred to as 5Ms and E.

6) The voice of the customer is usually expressed on the control chart as control limits - FALSE

Control limits are the voice of the process (different from specification limits, which are the voice of the customer). They show what the process is doing and act as a guide for what it should be doing. Control limits also indicate that a process event or measurement is likely to fall within that limit. Control limits are calculated from process data for a particular control chart whereas specification limits are defined by the customer and it appear on histograms, box plots, or probability plots.

7) Quality begins with control and inspection - TRUE

Quality control (QC) is an ongoing process that begins at the earliest stages of manufacturing. Selecting parts and materials to be used in production, training staff and calibrating equipment in the factory could all be considered part of overall QC.

“Inspection” as it relates to QC is an effort to check the manufactured goods to ensure they meet the customers’ specifications and quality standards. Inspection can occur at several stages before, during or after inspection, including:

a) Checking raw materials and parts before mass production (also called “incoming quality control”

b) First article inspection (FAI) - checking one or a few parts of the first batch coming off the production line

c) During production inspection (DUPRO) - checking finished goods, generally when 15–80% of the order is finished

d) Final inspection - checking finished goods, generally when 80% or more of the goods are finished.

e) Inspecting contain loading - checking a shipping container as workers load the finished and packaged goods

Inspection offers customers and manufacturers different benefits when performed at different times​.

8) Product quality is determined during the manufacturing of the product - TRUE

Quality can be broadly defined as meeting customer needs and expectations with a product. There are two types of needs or requirements from customers: Stated needs where a customer is able to state or describe what they want in a product and Unstated needs are needs or requirements that the customer takes for granted and needs that they don’t realize they have or think about.

This knowledge of the customer needs or requirements along with any requirements and manufacturer objectives for the product, should be captured in a customer requirements document.

These customer needs or requirements are then translated into product requirements or specifications. Once the requirements have been defined, design engineers should start by developing a high-level or conceptual design of the product.

The result of the product design activity should be various documents and files that describe the product design and how it will be manufactured (process design).

During development, analysis and developmental testing should be conducted to assure that the design approach will meet requirements.

The manufacturer should define the specifications that that the supplier must meet. The supplier is responsible for delivering the raw material or components to this agreed upon specification. The manufacturer is responsible for verifying that the raw materials or components meet its defined specifications.

Once product and process designs have been validated, the manufacturer should define inspection procedures to insure that production of the product will continue to meet the customer’s requirements. Thus product quality is determined during the manufacturing of the product.

9) Most companies operate at a 3 to 4 sigma level - FALSE

Six Sigma is a methodology designed to minimize defects in company’s output. The goal is to achieve six standard deviations (or 6.0 process sigma) between the mean and the nearest specification in regards to your organization’s processes, whether they are based on manufacturing, transactions, products or services.

Sigma levels which are less than 3 are not desirable. Companies with less than 3 sigma levels will not be able to survive in a competitive marketplace. After Sigma Level 3 the gains are very small. But these gains make a considerable difference to the overall cost of quality as explained in costs of poorly performing processes. Thus most of the companies operate at six sigma level.

Thus many companies which practice Six Sigma, regularly calculate their process sigma, so they can measure their efforts and look for chances to further improve.

10) The project charter serves as contract between project team and sponsor - TRUE

A project charter is the statement of scope, objectives and people who are participating in a project. It begins the process of defining the roles and responsibilities of those participants and outlines the objectives and goals of the project.

The project management charter serves as a reference document. It should outline these three main points.

a) The essence, the goals and objectives of the project and plan to reach and achieve these goals and objectives.

b) Provide a shared understanding of the project. The charter should communicate its value and/or reason for existence to every person who has a part in it, from the team to the project manager, stakeholders, sponsors, etc.

c) Act as a contract between the project sponsor, key stakeholders and the project team. By noting the responsibilities of each party involved in the project, everyone is clear what their duties are.

11) Once the project charter is develop and completed, it should not be changed in order to avoid confusion - FALSE

Any document on a project can be changed. The only requirement is that all changes must be reviewed, analyzed for impact on the constraints (Time, Cost, Scope, as well as Risk, Quality, Resources etc.,) and formally approved by the relevant authorities.

The Project Manager can approve any changes to the project, provided he/she has been awarded this authority.

But since the project charter is signed by the Project Sponsor (or any other manager external to the project – generally senior to the project manager), any changes to the project charter should also be approved by the Sponsor or the Change Control Board (CCB) appointed by the Sponsor.