Designing of control chart of extended EWMA statistic using repetitive sampling scheme

In this paper, we propose extended exponential weighted moving average (EEWMA) control chart (CC) for the surveillance the process mean using repetitive sampling scheme under the assumption that quality characteristic of a product is a quantitative variable following the normal distribution. Two control limits named as inner and outer control limits of the proposed CC are derived using the in-control process mean and variance. The necessary measures are derived to obtain the process in-control and out-of-control average run length (ARL) and tabulated for different process shifts and smoothing constants. Comparisons are made to check the capability of intended CC with the EEWMA CC and repetitive EWMA CC in term of ARL. It has been observed that the presented CC shows better results in term of early detection of divergence in process mean. A simulation study is carried out to illustrate the performance of the proposed CC. An industrial example has been incorporated for its practical purpose.