Six Sigma And Mathematical Statistics

Six Sigma firstly actualizes in Motorola at the end of 1980s. Then, in GE, it gets much more attention from GE's CEO Jack.Welch. Because of his great efforts, Six Sigma can be generalized from the leaders down to the operators. And the company gains giant profits. This makes Six Sigma be famous all over the world. In our country, many companies pay attention to Six Sigma at the end of 20 century, and in recent years, it set off a heat wave in Chinese companies. This paper is written under such background.Process management is the foundation of Six Sigma. Most of the projects are done through data analysis. So Six Sigma and Statistics are combined compactly, and most of the tools in Six Sigma have relation to Statistics. However, most of the tools of Six Sigma are not from Statistics directly but from Quality Management. Six Sigma is so different from Quality Management that it will take Six Sigma many problems.In this paper, We point out the disadvantages of the tools in Six Sigma according to Statistics. It will take many problems while doing projects in 6σ level with the tools in 3 σ level. In process controlling, it still uses Shewhart-charts in Six Sigma. Shewhart-charts have good effect in detecting big shift of process, but not small shift. We use CUSUM, EWMA, CCC control charts to improve such status. These control charts are all good at detecting high-quality processes.CUSUM, EWMA, CCC control charts develop well in theory, but not so good in practice, especially in China. The author is working in a company of telecom. We try to solve some problems in works by Six Sigma. Because of demands, we have improved the form of Six Sigma, do the project with the improved Six Sigma, and acquire good effect. In the process of doing the project, we apply the CCC-charts to solve problems, and achieve the goal. It's first time in China.In this paper, we also introduce the histories of Statistics, Quality Management and Six Sigma, and expound the relations among them. Then we give the contacts and differences between Six Sigma and 3σ Theory according to theory and practice. They are two hot topics in management area and quality area.