Abstract
This paper discusses how to control the process, whereby samples from the process are respectively classified into several categories by inspection. So far, when there are two categories. p chart or pn chart has been used, and when there are more categories, Chi-Square charts [1] Duncan proposed has been used. Recently, Tamaki et al. [6] proposed an advanced control chart based on Duncan's chart. These control charts are all based on the definition that the state of statistical control is the non-existence of variation between subgroups, and are designed by binomial distribution or multinomial distribution. However, a new control chart which considers variation between subgroups is required for the process control at the field in which many new products appear one after another in short cycle. This paper proposes a new control chart based on categorical data distributed as compound distribution and studies the level of significance of this chart.
