States that, under certain circumstances, a single • control chart with tightened control limits may be more effective for detecting process shifts than the combination of • and s control charts, while the type I error can be kept at the same level. A computer program is developed to decide...

The mean shifts (or range shifts, standard deviation shifts) of a process may be classified into a set of modes (or classifications), each of which is characterized by the shift magnitude (δ) and the occurrence probability, f. The knowledge relating to the shift modes is useful to the...

Studies the necessity of controlling the variation of the skewness of the process distribution in order to reduce the product scrap. Proposes a γ control chart for detecting the skewness shift, also implements a simulation procedure to decide the control limits of the γ chart.