Title: A unified generalised process capability index and its applications to logistic-exponential distributed characteristic
Authors: Mahendra Saha; Amartya Bhattacharya; Sukanta Pramanik; Sudhansu S. Maiti; Arindam Gupta
Addresses: Department of Statistics, University of Delhi, Delhi, India ' National Atlas and Thematic Mapping Organisation, GoI, CGO Complex, Kolkata, India ' Department of Statistics, Siliguri College, Siliguri, Darjeeling, India ' Department of Statistics, Visva-Bharati University, Santiniketan, India ' Department of Statistics, University of Burdwan, Burdwan, India
Abstract: The introduction of the process capability index has made it possible for industries to evaluate process performance and assess how well the final product meets consumer expectations. In this article, we take into consideration the six most popular estimation techniques, namely the maximum likelihood, least square, weighted least square, percentile, Cramèr-von-Mises, and maximum product of spacing techniques, in order to estimate the parameters and the new unified measure of the generalised process capability index, denoted as Cpy (u, v) for the logistic-exponential process distribution. Extensive simulations are carried out to investigate the performances of these considered classical estimation methods in terms of their respective biases and mean squared errors. Additionally, we contrast the results of three bootstrap confidence intervals of Cpy (u, v) in terms of average widths and coverage probabilities: standard bootstrap, percentile bootstrap, and bias-corrected percentile bootstrap. Two datasets related to the electronic industries are re-analysed in order to show the applicability of the suggested methodologies. [Submitted: 28 December 2022; Accepted: 17 October 2023]
Keywords: Monte-Carlo simulation; point and interval estimation; unified measure of process capability index.
European Journal of Industrial Engineering, 2025 Vol.19 No.4, pp.401 - 428
Received: 28 Dec 2022
Accepted: 17 Oct 2023
Published online: 02 Jun 2025 *