@article{Yahaya_Lim_Ibrahim_Yeong_Khoo_2023, title={A VARIABLE SAMPLE SIZE SYNTHETIC CHART FOR THE COEFFICIENT OF VARIATION}, volume={33}, url={https://sajie.journals.ac.za/pub/article/view/2545}, DOI={10.7166/33-1-2545}, abstractNote={<p>A variable sample size (VSS) synthetic chart to monitor the coefficient of variation  is proposed in this paper to improve the performance of the existing synthetic  chart. A description of how the chart operates, as well as the formulae for various performance measures (i.e., the average run length (<em>ARL</em>), standard deviation of the run length (<em>SDRL</em>), average sample size (<em>ASS</em>), and expected average run length (<em>EARL</em>)) are proposed. The algorithms that optimise the out-of-control <em>ARL</em> (<em>ARL</em><sub>1</sub>) and <em>EARL</em> (<em>EARL</em><sub>1</sub>), subject to the constraints in the in-control <em>ARL</em> (<em>ARL</em><sub>0</sub>) and <em>ASS</em> (<em>ASS</em><sub>0</sub>), are also proposed. Subsequently, optimal charting parameters for various numerical examples are obtained. The proposed chart shows a significant improvement over the existing synthetic -chart. Comparisons with other -charts also show that the proposed chart performs better than the Shewhart-  and VSS-  charts under all cases, while showing better performance than the exponentially weighted moving average (EWMA) and VSS EWMA-  charts for moderate and large shift sizes. Finally, this paper shows the implementation of the proposed chart on an actual industrial example.</p>}, number={1}, journal={The South African Journal of Industrial Engineering}, author={Yahaya, Masthura and Lim, Sok Li and Ibrahim, Adriana Irawati and Yeong, Wai Chung and Khoo, Michael Boon Chong}, year={2023}, month={Mar.}, pages={1–15} }