six sigma training(ppt 66)6sigma推行教本.ppt

BPTL Confidential 數据分布 數据分布 Many natural phenomena and man-made processes are observed to have normal distributions, or can be closely represented as normally distributed. For example, the length of a machined part is observed to vary about its mean due to: temperature drift, humidity change, vibrations, cutting angle variations, cutting tool wear, bearing wear, rotational speed variations, fixturing variations, raw material changes and contamination level changes If these sources of variation are small, independent and equally likely to be positive or negative, the length will closely approximate a normal distribution. 正態分布易于理解, 具有特性, 統計學提供了許多基于正態分布的強有力的分析方法來幫助人們做決定. 因此, 我們通常會試圖用正態分布去近似模擬其它分布 (如可能) 或轉化數据以“使”它遵從正態分布. 它是分析過程能力的首選分布形式. 正態分布的一些特性 A normal distribution can be completely described by knowing only the: Mean (m) Variance (s2) 正態分布的一些特性 正態分布的一些特性 The mean, median and mode all coincide at the same value - m. There is perfect symmetry. 正態分布的一些特性 The area under sections of the curve can be used to estimate the cumulative probability of a certain “event” occurring: 正態分布的一些特性 Let’s compute the cumulative probabilities of the following distributions: 正態分布的一些特性 MiniTab: Calc e Probability Distributions e Normal... The Focus of Six Sigma Identifying critical aspects of the business with problems or opportunities for improvement. Targeting those critical areas and designating improvement efforts as Six Sigma Black Belt projects. Selecting top people to work on the projects--full time. Ensuring these people have the time, tools, and resources they need to succeed. Customer Focus: A Model For Success Six Sigma Vision The Vision of Six Sigma is to delight customers by delivering world-class quality products through the achievement of Six Sigma levels of performance in everything we do. Six Sigma - Aggressive Goal Statistical Definition of n-Sigma Statistic