The R chart and the S2 chart are the usual charts for monitoring process dispersion; however, the double sampling (DS) scheme has only be used with the S2 chart. The difficulty in obtaining the properties of the DS R chart ...

The steady-state average run length (ARL) is a function of the in-control probabilities of being in each nonabsorbing state. Davis and Woodall (2002) tabulated values that are significantly smaller than the steady-state ...

In this paper, we consider the double sampling (DS) (X) over bar control chart for monitoring processes in which the observations can be represented as a first-order autoregressive moving average (ARMA(1, 1)) model. The ...

In this paper, we consider the double sampling (DS) (X) over bar control chart for monitoring processes in which the observations can be represented as a first-order autoregressive moving average (ARMA(1, 1)) model. The ...

In this article, we consider the use of 3 attribute charts—the npxy, the npw and the Max D charts—to control the covariance matrix of bivariate processes. In comparison with the generalized variance |S| chart, the 3 attribute ...

In this article, we propose the Trinomial - ATTRIVAR (T-ATTRIVAR) control chart where attribute and variable sample data are used to control the process mean. Firstly, two discriminating limits sort the sample items into ...

The usual practice in using X̅ control charts to monitor the mean of a process consists of taking at equally intervals samples of size n and compare with control limits. The purpose of this article is to propose an alternative ...

The control chart introduced by Shewhart is one of the most important quality control techniques used to detect special causes. Real world data are complicated to interpret since they involve a certain level of uncertainty ...

The -x control chart is an important tool for statistical process control. It is easy to analyze and implement, which is why its use in industry is very common. However, it does not perform well for small displacements ...