The Effect of Estimated Control Limits

  • JaiWook Baik (Department of Applied Statistics, Korea national Open University) ;
  • TaiYon Won (Department of Applied Statistics, Chung Ang University)
  • Published : 1998.12.01

Abstract

During the start-up of a process or in a job-shop environment conventional use of control charts may lead to erroneous results due to the limited number of subgroups used for the construction of control limits. This article considers the effect of using estimated control limits based on a limited number of subgroups. Especially we investigate the performance of $\overline{X}$ and R control charts when the data are independent, and X control chart when the data are serially correlated in terms of average run length(ARL) and standard deviation run length(SDRL) using simulation. It is found that the ARL and SDRL get larger as the number of subgroups used for the construction of the chart becomes smaller.

Keywords

References

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