A power approximation model for the joint determination of X and R control chart parameters

Discusses the problem of the joint determination of the parameters for X and R control charts. A simple heuristic, called a power approximation, is presented. The power approximation is based on three regression equations which are used to estimate the sample size and the control limits for the X chart and the R chart. Thereafter, some developments and discussion about the proposed power approximation are presented and the method’s performance is tested and assessed using a set of problems previously studied in various scientific publications, and also using a specific set of data from a previously published study.