Control charts for variation play a key role in the overall statistical process control (SPC) regime. We study the popular Shewhart-type S2, S and R control charts when the mean and the variance of a normally distributed process are both unknown and are estimated from m independent samples...

Nonparametric control charts do not require knowledge about the shape of the underlying distribution and can thus be attractive in certain situations. Two new Shewhart-type nonparametric control charts are proposed for monitoring the unknown location parameter of a continuous population in Phase...

Nonparametric control charts can provide a robust alternative in practice to the data analyst when there is a lack of knowledge about the underlying distribution. A nonparametric exponentially weighted moving average (NPEWMA) control chart combines the advantages of a nonparametric control chart...

Non-parametric procedures are presented for comparing several treatments with a control when the data are collected in a randomized complete block design with no interaction. The procedures are generalizations of some well-known sign-type tests, and include both overall tests and multiple...

The effects of parameter estimation are examined for the well-known c-chart for attributes data. The exact run length distribution is obtained for Phase II applications, when the true average number of non-conformities, c, is unknown, by conditioning on the observed number of non-conformities in...

Distribution-free (nonparametric) control charts provide a robust alternative to a data analyst when there is lack of knowledge about the underlying distribution. A two-sided nonparametric Phase II exponentially weighted moving average (EWMA) control chart, based on the exceedance statistics...

A class of tests is considered for testing equality of quantiles (of a specified order) of K ([greater-or-equal, slanted] 2) continuous populations when the observations are subject to random right-censorship. The tests may be viewed as a generalization of a class of tests considered by Sen...

A class of Shewhart-type distribution-free control charts is considered. A key advantage of these charts is that the in-control run length distribution is the same for all continuous process distributions. Exact expressions for the run length distribution and the average run length (ARL) are...