STATISTICAL PROCESS CONTROL METHOD USING THE DISTRIBUTION OF THE COEFFICIENT OF VARIATION AND NONCENTRAL T DISTRIBUTION

摘要

A method of controlling a statistical process by using distribution of variation coefficients and non-central t distribution are provided to precisely estimate a management limitation line by using a simple calculation. A statistical process management server includes a function producing unit(110), a management limitation line producing unit(112), a process management chart generating unit(114) and an output unit(116). The function producing unit produces a probability density function of variation coefficients based on a standard deviation of process coefficients. The management limitation line producing unit produces a management limitation line of the variation coefficients using a cumulative distribution function of the variation coefficients. The process management chart generating unit generates process management charts including the management limitation line. The output unit(116) outputs the variation coefficients to the process management chart.