A NOVEL APPROACH FOR ESTIMATING THE ARL-BIAS SEVERITY OF SHEWHART P-CHARTS
Journal Title: International Journal for Quality Research - Year 2018, Vol 12, Issue 1
Abstract
The Shewhart p-Chart is a widely used and taught control chart that monitors the process fraction of nonconforming, p. The control limits of this chart are computed from an equation derived from the central limit theorem that assumes the parameters p and sample size, n, provide a good approximation of the binomial to the normal distribution. It is known that if the approximation is poor the chart becomes ARL-biased with a consequent deterioration of its process improvement detection capability. Hence, if one is to use this chart its ARL-biased severity ought to be established in advance. Three parameters are used to estimate a chart's ARL-bias severity, namely the in-control ARL, the relative ARL-bias and the maximum out of control ARL. However, calculating these parameters is a task that requires of lengthy calculations that often entails the use of specialised software. In this paper we present a new approach that facilitates the estimation of the bias severity, this approach consists of a closed-form equation that eases the calculations of the ARL-bias parameters and of a graphical method that permits assessing a p-Chart's ARL-bias severity level according to the severity zone in which its n and p values fall into.
Authors and Affiliations
Marco Antonio Argoti, Andrés Carrión García
Keywords
Related Articles
- EP ID EP266432
- DOI 10.18421/IJQR12.01-12
- Views 79
- Downloads 0
QUALITY ASSESSMENT IN HIGHER EDUCATION: ARE RUSSIAN UNIVERSITIES FOCUSED ON THE EDUCATIONAL NEEDS OF STUDENTS?
The article touches on the issue of meeting the students’ educational needs as a crucial point in the quality of education improvement. The main consumers of educational services are students whose perceptions of the edu...
THE SUPERIOR CUSTOMER'S VALUE OF THE NEW ECONOMY IMPLEMENTED WITHIN MACEDONIAN COMPANIES
There is only one way towards a successful market economy. You must be better and faster than your rivals. Only those that might win the market with special products/services may secure their existence. Each company is c...
TECHNICAL PRODUCT RISK ASSESSMENT: STANDARDS, INTEGRATION IN THE ERM MODEL AND UNCERTAINTY MODELING
European Union has accomplished, through introducing New Approach to technical harmonization and standardization, a breakthrough in the field of technical products safety and in assessing their conformity, in such a mann...
THE DEVELOPMENT OF COMPLAINTS HANDLING STANDARDS IN SPA COMPANIES: A CASE STUDY ANALYSIS IN SPAIN
The aim of this paper is to analyze the key features of an effective complaint management process as well as to explore whether these systems are formally constituted in terms of standards or other models for complaints...
Modeling the Impact of New Approach Diresctives on Competitiveness of Enterprise
Determination of a product's phisical features is the responsibility of design engineering. This involves decisions related to the number of components, the role of each component, the choice of material, choice of metho...