A Research of Non-Normal Distribution Data Transformation

• Main Authors: Mei-Kuei Liu, 劉玫瑰
• Other Authors: Chuen-Sheng Cheng
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/26240460619428709701

碩士 === 元智大學 === 工業工程與管理學系 === 92 === It is always seen nowadays that the control chart and process capability index are commonly put in use in quality control process by the manufacturers. Because the control chart and process capability index are both established on the assumption of normal distribution, it is a necessity to confirm whether the data collected from real manufacturing process is normally distributed or not. This research therefore emphasizes on simulating different distribution types, parameters and sizes of samples with statistic software. When the raw data shows non-normal distribution after regular testing, it often leads to wrong judgments or decisions by managers and end users when the data is not properly transferred into normal distribution. The main purpose of this research is to introduce the application of Box-Cox power transformation to transfer the non-normal distributed data into a new normal distributed pattern, and then further statistical and analytical could be available. This study simulates six different common types of histograms in manufacturing process, and come up with transferring regulations which could lead to a practical transferring table for practical on-site applications. Finally these regulations could serve as a role model for transferring raw data into useful data which can be used by managers and end users for proper judging and appropriate decision making.