A sensitivity study for minimum cost np-charts

SUMMARY

In a previous paper the author has studied some properties of the minimum cost control schemes using np-charts. The process model involves nine independent data parameters whose values have to be estimated before an optimum np-chart can be determined. Since errors in estimation often occur in practice, the present paper investigates the extent to which these errors affect the optimality of the control procedure. Four parameters are found to have negligible effect, three to have moderate effect, and two to have critical effect. Rased on these results, a discussion is presented on the practicality of the economic approach.