A variable sampling interval run sum chart for the coefficient of variation. Issue 15 (13th October 2022)

• Record Type: Journal Article
• Authors: Yeong, W. C.; Lim, Sok Li; Khoo, Michael B. C.; Ng, Peh Sang; Chong, Z. L.
• Is Part Of: Journal of statistical computation and simulation. Volume 92:Issue 15(2022)
• Page Start: 3150
• Page End: 3166
• Publication Date: 2022-10-13
• Subjects: Average Time to Signal -- Control Charts -- Coefficient of Variation -- Run Sum -- Variable Sampling Interval; Mathematical statistics -- Data processing -- Periodicals; Digital computer simulation -- Periodicals; 519.5028505
• DOI: 10.1080/00949655.2022.2061486
• Languages: English
• ISSNs: 0094-9655

Abstract

Abstract : This paper proposes a variable sampling interval (VSI) run sum chart for the coefficient of variation ( γ ), where the sampling interval is varied according to the current cumulative scores. Formulae to evaluate various performance measures for the proposed chart are derived, and algorithms to optimize the performance of the proposed chart using these measures are developed. These algorithms are then implemented on several numerical examples. Comparisons show that varying the sampling interval improves the performance of the run sum γ chart. Furthermore, the VSI run sum γ chart outperforms several existing charts in the literature. Implementation based on an illustrative example shows that the VSI run sum γ chart reduces the time needed to detect an out-of-control signal compared with its fixed sampling interval (FSI) counterpart.