The statistical performance of double sampling X̃ control charts for correlation data

Double sampling X control chart (DS) which is a Shewhart-type chart can reduce sample size and detect small process shift fast. In real industries, process observations may be interdependent and correlated, and the statistical performance of DS X chart for the correlated data need to be re-evaluated. This article constructs the calculations of statistical indices of DS X charts for correlation data and performs a comparative study for investigating the performance distinction of DS X charts and other Shewhart-type charts. This comparative study indicates that DS X charts are the best choice for monitoring of correlated data.