Constructing Phase I Control Charts with Kernel Density Estimation

• Main Author: 盧美惠
• Other Authors: 洪志真
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/92939514007267666462

碩士 === 國立交通大學 === 統計學研究所 === 95 === When evaluating and/or comparing control chart, usually it is assumed that the in-control values of the parameters are known. In practice, control limits in Phase II process monitoring are often constructed using the parameter estimates obtained from Phase I analysis. When the Phase I data are not all from the in-control state, the estimated parameters is systematically biased. Consequently, the effectiveness of the control chart constructed based on these estimates is doubtful in Phase II process monitoring. The purpose of this paper is to propose a new method to estimate the in-control process mean based on kernel density estimator (KDE). Simulation studies show that the performance of the control chart constructed with kernel density estimator is better than that of conventional two methods, especially when the mean shift is large.