# How is Sigma calculated?

### 2 thoughts on “How is Sigma calculated?”

1. In the normal distribution, σ represents the standard deviation, μ represents the mean value. X = μ is the symmetric axis of the image
3σ principle is
. The probability of the value distributed in the (μ-σ, μ σ) is 0.6827
in the value distribution (μ-2σ, μ The probability in 2σ) is 0.9545
. The probability that the value is distributed in (μ-3σ, μ 3 σ) is 0.9973
The possibility of only less than 0.3%in the range of this range is less than 0.3%.
Extension information:
The introduction to Sigma into quality management, thanks to Motorola, an engineer of Motorola, Bill Smith (some website information shows that he entered Motorola in 1987).
In on the personal webpage of Mikel J. Harry, Bill Smith has been studying the relationship between potential defects and product failures as early as 1984. White paper associated with potential defects, design balance and product failure.
In the study of the relationship between manufacturing defects and product failure, Bill Smith obtained a conclusion that the product design includes six times the standard deviation (6 σ) in order to ensure that the product will not have defects from the source. , And create the concept of "Six Sigma" to describe the expectations of design balance and product quality.
Reference information Source: Baidu Baike-Sigma

2. 6 Sigma
1 Sigma = 690,000 mistakes / millions of operations
2 Sigma = 308,000 mistakes / millions of operations
3 Sigma = 66800 mistakes / millions of operations
4 Sigma = 6210 mistakes / millions of operations
5 Sigma = 230 mistakes / millions of operations
6 Sigma = 3.4 mistakes / million operations
7 Sigma = 0 mistakes / millions operations operation
S 6 Sigma
"σ" is the letter of Greek, which is a statistical unit used to measure a standard error in the total number. The defect rate of general enterprises is about 3 to 4 Sigma. In terms of 4 Sigma, it is equivalent to 6210 errors in each million opportunities. If the enterprise continues to pursue quality improvement and reach the level of 6 Sigma, the performance will be almost perfectly achieved customer requirements. In one million opportunities, only 3.4 flaws can be found.
6 Sigma (6sigma) has evolved from a comprehensive quality management method in the mid -1990s to a highly effective corporate process design, improvement and optimization technology, and provided a series of equal applications for design, production and production and production and production and production. New product development tool for service. Then go hand in line with globalization, product services, e -commerce and other strategies, becoming the most important strategic measures for companies in the world to pursue excellence in management. 6 Sigma has gradually developed into a ruler of corporate strategic goals and product development design with customers as the main body, and pursue a quality management philosophy of continuous progress.

6 The main principles of Sigma (1)
When promoting 6 Sigma, enterprises must really achieve great results, and they must treat 6 Sigma as a management philosophy. There are six important subjects in this philosophy. There are many tools and methods behind each subject to support.

6 The main principles of Sigma (2)
 sincerely care for customers.

6 Sigma put customers first. For example, when measured the performance of the department or employee, you must think from the perspective of customers. First understand what the customer's needs are, then set corporate goals for these needs, and measure performance.
6 The main principles of Sigma (3)
 Managed according to data and facts.

. In recent years, although knowledge management has gradually been valued, most companies still make decisions based on opinions and assumptions. 6 The primary rules of Sigma are clarity. To evaluate performance, what measures should be done (), and then use data and analysis to understand how much gap between the company's performance distance.
6 The main principles of Sigma (4)
 The process is the heavy.

Whether it is a design product or improved customer satisfaction, 6 Sigma regards the process as a transportation to success, and it is a way to provide customer value and competitive advantage.

6 The main principles of Sigma (5)
 Active management.

The enterprises must often take the initiative to do things that general companies often ignore, such as setting a large goal and continuous review; set clear priority; emphasize prevention rather than fire saving; often question "Why why why why why is it "We must do this, instead of saying" we all do this. "
6 The main principles of Sigma (6)
 Co -working cooperation has no boundaries.

The cooperation between the cooperative relationship between the company's internal departments, between the company and the supplier, the company, and the customer can bring huge business opportunities to the company. 6 Siegma emphasizes unprecedented cooperation, allowing employees to understand how they should cooperate with the organizational direction of the organization, and measure the correlation between the activities of various departments in the processes of the enterprise. ,
6 The main principles of Sigma (seven)
 pursuing perfection, but at the same time tolerated failure.

In 6 Sigma companies, employees constantly pursue a method that can provide better services and reduce costs. Enterprises continue to pursue more perfect, but they can also accept or deal with occasional frustrations and learn from errors.

Who is 6 Sigma Quality
The product quality of a company is the result of the entire operation of this company. There are many factors that have a lot of influence and are intricate. Motorola has marked its goals with 6 Sigma quality, making complex problems easier to understand. The significance of the quality level of 6 Sigma at Motorola is as follows:

 1. 3.4ppm (the number of adverse rates or disadvantages is 3.4th)

2. 9999966% The product is no shortcomings.

3. Provide a benchmark comparison with competitors to provide a measurement benchmark for TQM.

4. You can understand how long the distance is.

why the quality of 6 Sigma attracts us
6 Sigma's quality has attracted many companies. The benchmark.

2. Using 6 Sigma quality can measure the quality gap between your company and competitors.

3. Show the progress towards no shortcomings.

4. Provide a clear goal for each department.

Who is 6 Sigma Management (1)
 is a comprehensive management system and development strategy of gaining and maintaining the success of the enterprise and maximizing its operating performance. It is a way to enable enterprises to gain rapid growth.

The improvement of business performance includes:
• Increase market share
• Increase the customer's return rate
n • Deficiency reduction rate
• Product/service development accelerates
• Corporate culture changes

what is 6 Sigma Management (2)
The process of innovation by leading and driven by the company's top managers. The goal of improving/innovation is proposed by the highest management (this goal is closely related to the development strategy of the enterprise), the resource and time framework.
• This innovation method is core of the structured improvement process of definition, measurement, analysis, improvement, and control (DMAIC).
DMAIC for three basic improvement processes:
6 Sigma product/service implementation process improvement
6 SSDP
, "Big Black Belt MBB" and "Black Belt BB" and "Green Belt GB" level four have clearly trained personnel as organizational guarantees.

The innovative method emphasizes the use of quantitative methods/tools, and emphasizes the detailed definition of customer needs/satisfaction in quantitative expression. Each stage has clear goals and assisted by the corresponding tools or methods.

Why use 6 Sigma Management (1)
to survive:

"Why should you carry out 6 Sigma management?" Motorola's answer is: for survival.

From the 1970s to the 1980s, Motorola lost the radio and TV market in competition with Japan, and later lost the market for BP and semiconductor. In 1985, the company faced closure.

The Japanese company acquired Motorola's TV production company in the 1970s. After the Japanese transformation, production was quickly put into production, and the adverse rate was only 1/20 when Motorola was managed. They use the same personnel, technology and design. Obviously the problem is in the management of Motorola.

In market competition, the harsh survival reality allowed Motorola's senior management to accept such a conclusion: "Our quality is stinky." Under the leadership of its CEO, Motorola started the road of 6 Sigma. Today, "Motorola" became a world -renowned brand. In 1998, Motorola won the United States Baldicic National Quality Management Award. Their success of their success is the road of 6 Sigma. It is 6 Siegma Management that enables Motorola's leading company from the closure to its world -renowned quality and profit.

Why use 6 Sigma Management (2)
to get the core ability:

. Essence Whether an enterprise can survive depends on the value provided by the company to the market/customers. According to the theory of economics:
. Essence Essence Essence Q quality
v value = --------
. Essence Essence Essence P price
. Essence 6 Core Corporation of Sigma: Improve quality, reduce costs, maximize value, and customer satisfaction/strong market competitiveness.

How to push 6 Sigma
It in the process of pursuing 6 Sigma, there are many methods and tools. One of the important methods is a five-stage improvement step DMAIC (pronounced deh-maiik): definition, measure, analysis, improvement, and control (control). Through these steps, the investment rate of investment will naturally increase.
定 definition
defined core processes and key customers, standing from the customer's position, and finding the most important matters for them, that is, "CRITICAL TO Quality" (CTQ). Clarify the team's articles of association and the core business process.
量 measuring
In the key evaluation, which is to establish the basic steps for the flaws in the process. Personnel must take
The training and statistical analysis software and measurement analysis. In order not to create a heavy burden on employees, people who have six standard deviations can be carried out with the training with novice to help novices overcome difficulties. For complex calculations, you can provide automatic calculation tools to reduce the time required for complex calculations.
analysis
The root cause of the inquiry error. Use statistical analysis to detect the potential variables that affect the results, and find out the most important source of the flaw. The tools used include many statistical analysis tools.
Improved
In the best solution, and then draw up the action plan, which is indeed executed. This step needs to be continuously tested to see if the improvement plan can really play a effect and reduce errors.
control
Keng to ensure that the improvement of the done can continue. It is not possible to measure errors to avoid errors. In the past many process improvement plans, the concept of control is often ignored; among the six standard deviations, control is the key to its long -term improvement of quality and cost.
If successful promotion, 6 Sigma brings will change the inertia of the enterprise, allow employees to constantly ask questions, and seek better solutions, so that enterprises are often on the slope of climbing upward.

6 The promoters of Sigma
 Some people say: GE President Mr. Welch is an expert in creating talents. It was he cultivated thousands of talents who created wealth for enterprises in GE's 6 Siegma management. They are called warriors, big black belts, black belts and green belts. These personnel come from various positions of the enterprise. After 6 Sigma special training, it provides organizational guarantee for 6 Sigma management. And the big black belt and black belt of the 6 Sigma project have become the wealth of the enterprise. Many black belt personnel have entered the corporate leadership position after the term of the 6th Siegma project that ended two years.

Warriors: The manager of 6 Sigma is responsible for the implementation of 6 Sigma. Responsible for deploying the implementation of Sigma and all support work. Responsible for determining or selected 6 Sigma projects. Track or supervise the progress of 6 Sigma.

Big black belt: 6 Sigma's implementation technology is always responsible. Assist the Warriors to select the project, formulate implementation plans and time frames, and provide support for 6 Sigma senior technical tools to black belts, and be responsible for mobilization, coordination, and communication.

Black belts: Various departments from the enterprise, after a comprehensive training of the 6 Sigma innovation process and tools, are familiar with the 6 Siegma innovation process and are responsible for guiding or leading the improvement project. Provide training and guidance for green belts. He has been engaged in the term of the black belt for 2 years. 1 black belt completes 5-7 projects per year, with a cost of about 1 million.

Green belt: After training, personnel participating in the 6 Sigma project in their posts.

The personnel ratio: every 1,000 employees
. Essence Big black belt: 1
. Essence Black belt: 10
. Essence Green belt: 50-70

6 Sigma support technology
 measuring technology:

• DPMO calculation method
• Process ability analysis technology (including the process ability analysis technology (including Analysis of long/short -term process ability)
 Basic technology:

new, old seven tools

• SPC measurement, analysis, analysis, analysis, analysis, analysis, analysis, analysis, analysis, analysis , Fluctuations of improvement and monitoring processes
• DOE/Tiankou method optimization design technology, through DOE, improve the process design, make the process ability to reach the optimal
• FMEA risk analysis technology, assisted to determine improvement projects, formulate improvement improvement Target
• QFD customer demand analysis technology, assisting the customer's needs correctly into internal work requirements
• Methods that are fundamentally prevented from accidentally prevent errors
n Soft technology:

• Improve team work efficiency
• Employee ability and authorization
• communication and feedback
6 The influence of
The when it comes to corporate culture, it seems to make people feel abstract. However, if you carefully observe the concepts, value orientation and behavioral criteria that people around you are dealing with the simplest and small issues, you will not feel it if you feel its existence. Simply put, corporate culture is "the way we do things here." When you try to improve the quality, especially through the improvement of the work process (including processing, service, administration and management, etc.) to obtain the best product and service quality, the culture shows huge resistance.

Therefore, Mr. Hodgage pointed out:
(1) When strategic and culture conflict, culture is constant;
(2) When the spirit of corporate culture and change When not compatible, the efforts of change will fail.

Mrly summarized the 20 lesson lessons of the Baldrech Award -winning companies. Analyzing the lessons of these successful companies, especially the lessons in corporate culture construction at the top of the top -level position. It is not difficult to find that successful companies have taken one more step than other companies when implementing a quality strategy. That is, while they are committed to the improvement of product and service quality, they will spend great efforts to transform their corporate culture that they are not suitable for the quality of 6 Sigma, so as to keep all employees' beliefs, attitudes, values ​​and expectations, and the quality of 6 Sigma and 6 Sigma quality. Synchronize. In order to create a good corporate quality and culture, ensure the success of the 6 Sigma quality strategy.
Successful examples (1)
GE company Jack Welch

6 Sigma "is the most important development strategy that GE has never experienced. 6 Sigma;

The cost income of the Sigma Festival is 300 million US dollars/1997, 750 million US dollars/1998, 1.5 billion US dollars/1999;
n Raise to 16.7%/1998

The market value exceeds 30 billion US dollars

jack Welch formulate three major development strategies for GE: 6 Sigma, product services, globalization, so that GE quickly makes GE quickly Developed into the world's largest and most successful multinational group.

Successful examples (2)
LARRY BOSSIDY
n
The earnings of 6 Sigma cumulative accumulation of more than 2 billion US dollars

The profit margin exceeding 14%/1999

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