The EWMA Wilcoxon Signed-Rank Chart with Variable Sampling Interval
-
Mohammed Kadhim Shanshool
,
Shashibhushan B. Mahadik
and
Dadasaheb G. Godase
Abstract
In this paper, we propose a nonparametric exponentially weighted moving average (EWMA) control chart with a variable sampling interval (VSI) for monitoring the median of a continuous symmetric process distribution. The proposed chart, referred to as the VSI EWMA WSR chart, is based on the Wilcoxon Signed-Rank (WSR) test. Its out-of-control statistical performance is numerically compared with that of the fixed sampling interval (FSI) EWMA WSR chart when the underlying process distributions are normal, uniform, Laplace, scaled Student’s t, and logistic. The metric used for the performance comparisons is the steady-state average time to signal, which is determined through Monte Carlo simulations. The simulation results reveal that the VSI EWMA WSR chart significantly outperforms the FSI EWMA WSR chart in detecting the median shifts of all sizes across all distributions. The practical utility of the proposed chart is demonstrated using both simulated and real datasets. Our findings underscore the efficacy of the VSI EWMA WSR chart, highlighting its value as a tool for quality control in manufacturing and other industries.
Funding statement: Mohammed Kadhim Shanshool’s work was supported by the Indian Council for Cultural Relations, India (2-172/2021-22/ISD-II).
Acknowledgements
The authors sincerely thank the editor and reviewer for their valuable comments and constructive suggestions, which have significantly enhanced the quality and clarity of the paper.
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Articles in the same Issue
- Frontmatter
- Classical and Bayesian Estimation of PCI 𝒞pc Using Power Generalized Weibull Distribution
- A τ-Power Stochastic Rayleigh Diffusion Model: Computational Aspects, Simulation and Predictive Analysis
- Acceptance Sampling Plans for Truncated Life Tests Using the Marshall–Olkin Birnbaum–Saunders Distribution
- The EWMA Wilcoxon Signed-Rank Chart with Variable Sampling Interval
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Articles in the same Issue
- Frontmatter
- Classical and Bayesian Estimation of PCI 𝒞pc Using Power Generalized Weibull Distribution
- A τ-Power Stochastic Rayleigh Diffusion Model: Computational Aspects, Simulation and Predictive Analysis
- Acceptance Sampling Plans for Truncated Life Tests Using the Marshall–Olkin Birnbaum–Saunders Distribution
- The EWMA Wilcoxon Signed-Rank Chart with Variable Sampling Interval
- A New Synthetic Triple Sampling X̅ Control Chart
- From Quantile Functions to Subquantile Functions and Their Applications
