Determine the Average Runs Lengths for The Double Exponentially Weighted Moving Average control Charts Using Repetitive Sampling

Abstract

We use repetitive sampling for exponentially weighted moving average (EWMA) control charts, and an extension of the exponentially weighted moving average (EWMA) technique to a DEWMA technique, to improve the efficiency for these control charts to detect small process mean positive shifts for a normally distributed process variable. Also, we present the formulas which is used to compute the average runs lengths under control and out of control. We used the DEWMA when the smoothing parameter is equal to .

Also, we used the EWMA and DEWMA control charts using repetitive sampling technique for monitoring a process mean when the observations (products are selected from al_mamun factory) are identically and independently distributed (iid) from normal distribution in continuous manufacturing. We assumed several values for the parameters of the EWMA and DEWMA control charts using repetitive sampling technique, such as the values of the process mean positive shifts and the smoothing parameters and for two values of control charts constants using Matlab -R2018a.