On The Use Of Pooled Shewhart-Cusum Control Chart For Monitoring Process Mean Using Sampling Methods
Ismaila O Adegbite
Department of Statistics, Osun State Polytechnic, Iree, Osun State, Nigeria
Joseph O Braimah
Department of Mathematics, Faculty of Physical Sciences, Ambrose Alli University, Ekpoma, Edo State, Nigeria
Adedotun O Omisore
Department of Statistics, Osun State Polytechnic, Iree, Osun State, Nigeria
Liasu A Ayinde
Department of Statistics, Osun State Polytechnic, Iree, Osun State, Nigeria
Keywords: Upper Control limit, Lower Control Limit, Reference Value, Target Value, Out of Control
Abstract
This paper is aimed at developing a Pooled Shewhart-Cumulative Sum (CUSUM) control chart in monitoring a sensitive wide range of mean shifts. In order to improve the effectiveness of the Pooled Shewhart-CUSUM control chart, ranked set sampling and median ranked set sampling was used as an alternative of a simple random sampling (SRS). Analysis on mean and variance, average run length properties of the Pooled Shewhart-CUSUM with each of the sampling methods was carried out and their performance was also compared. The study confirmed that the median ranked set sampling resulted to minimum variance with best protection against different types of process shifts followed by ranked set sampling than the simple random sampling.