A short note on the effect of sample size on the estimation error in Cp. Issue Volume 28:Issues 4(2016) (1st October 2016)

• Record Type: Journal Article
• Authors: Sedighi Maman, Zahra; Murphy, W. Wade; Maghsoodloo, Saeed; Haji Ahmadi, Fatemah; Megahed, Fadel M.
• Is Part Of: Quality engineering. Volume 28:Issues 4(2016)
• Page Start: 455
• Page End: 466
• Publication Date: 2016-10-01
• Subjects: absolute percentage error -- Phase I -- process capability -- six sigma -- standard deviation; Quality control -- Periodicals; Production management -- Quality control -- Periodicals; 658.5
• DOI: 10.1080/08982112.2016.1172091
• Languages: English
• ISSNs: 0898-2112

Abstract

ABSTRACT: Process capability indices such as Cp are used extensively in manufacturing industries to assess processes in order to decide about purchasing. In practice, the parameter for calculating Cp is rarely known and is frequently replaced with estimates from an in-control reference sample. This article explores the optimal sample size required to achieve a desired error of estimation using absolute percentage error of different Cp estimates. Moreover, some practical tools are created to allow practitioners to find sample size in different situations.