Abstract In a production process, when quality of the product depends on more than one characteristic, ‘Multivariate Quality Control’ ( MQC ) techniques are used. Many MQC techniques have been developed to control multivariate variable processes, but not much work has been reported on...

Abstract Control charts for high quality processes based on counting cumulative conforming items have attracted a lot of attention recently. However, such charting procedures usually apply when items are inspected one by one. There are situations that products are inspected sample by sample for...

Abstract In this paper the use of Collani's statistic for monitoring simultaneously process mean and process variance is investigated by a comparison with the more popular chart and chart, respectively. The comparison is performed by means of an economic design of the charts assuming two...

Abstract In this paper, we propose a bivariate Weibull regression models for survival time derived from the bivariate exponential distribution of Freund [Freund, Journal of the Amer. Statist. Assoc. 56: 971-77, 1961]. There are some biometrical applications which motivated to study these...

Abstract Taguchi defined product quality in a universal way by adopting a quadratic quality loss function. In 1987, Kapur and Wang addressed the problem of setting economic specification limits for processes being not capable to meet given tolerances and, therefore, product quality has to be...

Abstract The well known inverse Rayleigh distribution is considered as a model for a life time random variable. The problem of acceptance sampling when the life test is truncated at a pre-assigned time is discussed. For various acceptance numbers, various confidence levels and various values of...

Abstract In this paper, we present a simple proof of a result, which has useful applications in the context of shock models that are important in reliability theory. Though the result can be easily proved using properties of totally positive functions, we introduce a new idea which enables us to...

Abstract Reliable predictions by means of quantiles constitute one of the most important tasks not only in statistics but in entire science. Quantiles may be estimated by using Extreme- Value Theory (EVT). However, the properties of many estimators based on this theory depend heavily on the...

Abstract Average run length is the most popular measure to assess the statistical performance of a control chart procedure. This paper discusses the limitations of the traditional average run length measure and introduces the concept of ‘unity’ average run length which is the ratio of the...

Abstract The global competition requires and the improved possibilities of data collecting and data analysis enables implementation of so-called continuous improvement strategies . Such a strategy can be divided into two parts, one which identifies room for improvement and a second one which...