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.