Control charts are extensively used in many real world applications. Since process parameters are rarely known, common practice is to estimate them. Then, the control limits are modified and become actually random variables. In this paper, we deal with the univariate control charts for...

The EWMA control chart is used to detect small shifts in a process. It has been shown that, for certain values of the smoothing parameter, the EWMA chart for the mean is robust to non normality. In this article, we examine the case of non normality in the EWMA charts for the dispersion. It is...

The nexus between inflation and its uncertainty has been a topic of wide dispute. Using wavelet decomposition and with special reference to Egypt for the period 1960-2013, we find that the focal relationship varies substantially among the different frequencies involved. In the short-run,...

To effectively assess the link between exchange rate uncertainty and exports performance in Egypt, this article relies on an optimal GARCH model among decomposed series on a scale-by-scale basis via wavelet approach. The observed outcomes reveal that the focal connection depends substantially on...

Measurement error is a usually met distortion factor in real-world applications that influences the outcome of a process. In this paper, we examine the effect of measurement error on the ability of the EWMA control chart to detect out-of-control situations. The model used is the one involving...

Control Charts are the main tools of Statistical Process Control. They are used for deciding whether a process is statistically stable or not. Much theory and many applications have been developed for the Gaussian (Normal) distribution in this area. However, in real data sets we usually face up...