Statistical quality control: A case study research

In this paper, statistical quality control of a production line has been presented using the classical method Shewhart, cumulative sum method (CUSUM) and Exponentially Weighted Moving Average (EWMA). The Shewhart technique can be utilized in controlling the process in which there are big changes in mean. The cumulative sum method is more efficient in detecting small changes in the mean. The EWMA includes the two techniques, as limited cases, since when λ = 1 the exponential smooth model is equivalent to the Shewhart technique, and when λ = 0 equivalent to the cumulative sum technique.