Design of the (T_U, T_L) Simultaneous Control Chart : A Study of the Multiple Decision on Continuous Distribution Observed as Attribute (1)

Abstract

This paper presents a new control chart, (T_U, T_L)simultaneous control chart, which enables us to make a multiple decision on parameters μand σfor originally normally distributed characteristics when it is observed as attribute data.In this method, a random variable normally distributed with N(μ, σ^2) is observed as attribute data (N_U, N_L) trinomially distributed with TN(n, π_U, π_L) by both-sided specification limits S'_U and S'_L and then each pair of data (N_U, N_L) is plotted on two dimensional simultaneous control chart to judge whether the process is under control or not.If the process is judged as out of control, then multiple decision on μand σ namely, specified interence on the change of μand σ, is made by this control chart.