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Supplier selection by estimation and testing of differences between two process capability indices

Mahendra Saha, Sanku Dey

Abstract


Boyles (1994) proposed a measurement formula for the production yield of normal processes called Spk, which establishes the relationship between the manufacturing specifications and the actual process performance. In this article, we use this index to obtain the difference between two indices (Spk1 −Spk2) to select the better process capability of two processes or manufacturers (or suppliers). The difference between two process capability indices (Spk1 −Spk2), cannot be inferred statistically because of the complexity of the sampling probability theory. Thus, we utilize bootstrap methods namely, standard bootstrap (SB), percentile bootstrap (PB) and bias-corrected percentile bootstrap (BCPB) for the difference between two indices (Spk1 −Spk2) to obtain bootstrap confidence intervals (BCIs) through simulation study. In order to compare the proposed BCIs of (Spk1 −Spk2) in terms of coverage probabilities (CPs) and average width (AW) we carried out a Monte Carlo simulation study. Results of the simulation study show that the AW of the BCPB confidence interval performs better than other bootstrap methods. To illustrate the application of BCIs of (Spk1 −Spk2), one real data set is analyzed.


Keywords


Bootstrap confidence intervals; maximum likelihood estimate; normal distribution; process capability index.

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References


J. C., Lee; H. N. Hung; W. L. Pear; T. L. Kueng; On the distribution of the estimated process yield index Spk, Quality and Reliability Engineering International, 18(2), 111-116 (2002).

J. K Kanichukattu; J. A. Luke; Comparison between two process capability indices using generalized confidence intervals, International Journal of Advanced Manufacturing Technology, 69 2793-2798 (2013).

J. M. Juran; Quality control handbook. 3rd ed. New York: McGraw-Hill. (1974).

J. P. Chen; K. L. Chen;Supplier selection by testing the process incapability index, International Journal of Production Research, 44(3) 589-600 (2006).

J. P. Chen; K. S. Chen; Comparison of two process capabilities by using indices Cpm: an application to a color STN display, International Journal of Quality and Reliability Management, 21(1) 90-101 (2004).

J. P. Chen; L. I. Tong; Bootstrap confidence interval of the difference between two process capability indices, International Journal of Advanced Manufacturing Technology, 21, 249-256 (2003).

J. Tosasukul; K. Budsaba; A. Volodin; Dependent bootstrap confidence intervals for a population mean, Thailand Statistician, 7(1) 43-51(2009).

K. S. Chen; W. L.; P. C. Lin; Capability measures for processes with multiple Characteristics, Quality and Reliability Engineering International, 19 101-110 (2003).

L. K., Chan; S. W. Cheng; F. A. Spiring; A new measure of process capability, Cpm. Journal of Quality Technology, 20(3) 162-175(1988).

L.I. Tong; H. T. Chen; Y. F. Tai; Constructing BCabootstrap confidence interval for the difference between two non-normal process capability indices CNpmk, Quality Engineering, 20 209-220(2008).

M. Perakis; Estimation of differences between process capability indices CpmorCpmkfor two processes, Journal of Statistical Computation and Simulation, 80(3) 315-334(2010).

R. A. Boyles; Process capability with asymmetric tolerances,Communications in Statistics -Simulation and Computation, 23(3) 615-643 (1994).

R. Ihaka; R. R. Gentleman; A language for data analysis and graphics,Journal of Computational and Graphical Statistics, 5 299-314(1996).

S. Dey; M. Saha, Bootstrap confidence intervals of the difference between two generalized process capability indices for inverse Lindley distribution, Life Circle Reliability and Safety Engineering, 7 89-96 M. (2018).

S. Kumar; S. Dey; M. Saha; Comparison between two generalized process capability indices for Burr XII distribution using bootstrap confidence intervals.Life Cycle Reliability and Safety Engineering, https://doi.org/10.1007/s41872-01900092-1. (2019).

T. C. Hsiang; G. Taguchi; A tutorial on quality control and assurance -the Taguchi methods. ,ASA Annual Meeting, Las Vegas, Nevada, 188. (1985).

V. E. Kane; Process capability indices. Journal of Quality Technology, 18(1) 41-52 (1986).

W. L. Pearn; S. Kotz; N. L. Johnson; Distributional and inferential properties of process capability indices,Journal of Quality Technology, 24, 216-231(1992).

W. L. Pearn; Y.C. Cheng; Estimating process yield based on Spkfor multiple samples, International Journal of Production Research, 45(1) 49-64(2007).

W. L., Pearn; G. H. Lin; K. H. Wang; Normal approximation to the distribution of the estimated yield index Spk, Quality and Quantity, 38(1) 95-111(2004).


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