An adaptive control chart for the process location based on ranked set sampling

Abstract

Several studies confirm the greater efficiency of estimators based on ranked set sampling (RSS) when compared to the corresponding ones obtained via simple random sampling (SRS). Recently, ranked set sampling has been considered in statistical process control. In this work, we propose the construction of adaptive control charts based on ranked set sampling. The adaptive strategy uses variable sample sizes and multiple dependent state sampling. Through an extensive simulation study, we verified that the proposed control charts have better performance (lower average number of samples until an out-of-control signal) when compared to the non-adaptive framework via RSS and adaptive via SRS. An illustration with simulated data complements this study.