New Dual Auxiliary Information-Based EWMA Control Chart with an Application in Physicochemical Parameters of Ground Water

Abstract

Exponentially weighted moving average (EWMA) control chart structures have been constructed based on simple random sampling under the effect of auxiliary information at a single stage. In this article, we have proposed generalized EWMA control chart structures for known and unknown parameters by considering the dual role of auxiliary information. The dual role of auxiliary information has incorporated through regression-type estimator under ranked set strategies. Results illustrated that proposed design structures perform outstandingly as compared to existing schemes. The performance of different control charts has evaluated through various performance measures. Moreover, the design structure for unknown parameters behaves like the design structure for known parameters. It implies that design structure for unknown parameters has the ability to resolve the issue of existing control charts when parameters are estimated. In addition, the significance of the proposed schemes has proved through a real-life example from an agricultural scenario in which monitoring of physicochemical parameters of groundwater is highlighted.