On scale parameter monitoring of the Rayleigh distributed data using a new design

In recent years, many supplementary designs have been developed incorporating the assumption that data follow the particular non-normal distribution. The V_R-control chart is one such design proposed to monitor the parameter σ² of the single parameter Rayleigh distributed data. Commonly, in authentic situations, practitioners need to estimate the scale parameter σ in the observed processes instead of σ². However, the positive square root of the V_R-statistic used in the existing design of V_R-control chart is not an unbiased estimator of σ and thus could not be practiced to monitor the scale parameter σ of the Rayleigh distributed process. A new structure of the V_R-control chart namely V_SQR for monitoring the scale parameter of the Rayleigh distributed data has been originally developed in this study. The statistical basis of this newly V_SQR design in terms of average run length (ARL), characteristic function and power curve have been derived. The analytical results are utilized further to determine the parameters of V_SQR-chart and in comparing the performance of the proposed control chart with existing competitors. Comparative results illustrate the effectiveness of the proposed design in view of statistical power. Finally, the computational procedure of this newly V_SQR-chart has been demonstrated using simulated data and real data on the breaking strength of carbon fibers.