Modified Double Sampling Control Chart for Monitoring The Coefficient of Variation
01 Aug 2019-Vol. 598, Iss: 1, pp 012110
TL;DR: In this paper, a modified double sampling (DS) chart for monitoring the coefficient of variation (CV) is proposed, denoted DS-G chart, in order to improve the sensitivity of previous DS chart.
Abstract: Monitoring the coefficient of variation (CV) has received wide attention in quality control, mainly used when the process mean and standard deviation are not constant. This work proposes a modified Double Sampling (DS) chart for monitoring the CV, denoted DS-G chart, in order to improve the sensitivity of previous DS chart for monitoring the CV, denoted DS-γ chart. Some numerical results for statistical properties of the proposed chart and performance comparisons are provided in the form of tables. Based on the average number of observation to signal (ANOS) performance, the proposed DS-G chart outperforms the DS-γ chart.
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TL;DR: In this paper, double sampling monitoring schemes implement a two-stage strategy to decide whether the process being monitored is in-control or out-of-control, based on the acceptance sampling field.
Abstract: Adapted from the acceptance sampling field, the double sampling monitoring schemes implement a two-stage strategy to decide whether the process being monitored is in-control or out-of-control. That...
2 citations
Dissertation•
01 Dec 2019
TL;DR: In this article , the authors explored the control charts to obtain the overview of the daily new COVID-19 cases number, which is considered as a production process, and observed and monitored using P-control chart.
Abstract: The COVID-19's rapidly spread in Indonesia is a serious concern for government. Various government policies, such as large-scale social restrictions, which is called as PSBB, and the imposing restrictions on community activities, be called as PPKM, have been applied to slow the spread of COVID-19. These policies were supposed to control people activities in many areas, especially that will invite the crowd happening. In this paper, the control charts be explored to obtain the overview of the daily new COVID-19 cases number, which is considered as a production process. The proportion of positive COVID-19 cases be observed and monitored using P-control chart. The data used is from the specimen COVID-19 test in DKI Jakarta Province, since April 2020 to January 2021. It is obtained that the process of daily new COVID-19 cases number has not been statistically controlled. It is detected some mean shifts of proportion in some point of times. Several findings indicate an upward trend, suggesting that the proportion of positive cases COVID-19 is rising. The public's conduct in Jakarta has served as a model for the government in designing policies to tackle the spread of Covid-19. However, due to the high mobility of Jakarta residents and its lack of consistency in the region, the COVID-19 process still remained out of control. © 2022 American Institute of Physics Inc.. All rights reserved.
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TL;DR: The mathematical relationship between the coefficient of variation associated with repeated measurements from quantitative assays and the expected fraction of pairs of those measurements that differ by at least some given factor is derived, i.e., the expected frequency of disparate results that are due to assay variability rather than true differences.
Abstract: We have derived the mathematical relationship between the coefficient of variation associated with repeated measurements from quantitative assays and the expected fraction of pairs of those measurements that differ by at least some given factor, i.e., the expected frequency of disparate results that are due to assay variability rather than true differences. Knowledge of this frequency helps determine what magnitudes of differences can be expected by chance alone when the particular coefficient of variation is in effect. This frequency is an operational index of variability in the sense that it indicates the probability of observing a particular disparity between two measurements under the assumption that they measure the same quantity. Thus the frequency or probability becomes the basis for assessing if an assay is sufficiently precise. This assessment also provides a standard for determining if two assay results for the same subject, separated by an intervention such as vaccination or infection, differ by more than expected from the variation of the assay, thus indicating an intervention effect. Data from an international collaborative study are used to illustrate the application of this proposed interpretation of the coefficient of variation, and they also provide support for the assumptions used in the mathematical derivation.
599 citations
Journal Article•
TL;DR: In this article, the double sampling X chart is proposed, which is the counterpart to double sampling plans, which offers better statistical efficiency (in terms of statistical efficiency) than double sampling plan.
Abstract: The purpose of this paper is to propose a new control chart, the double sampling X chart, which is the counterpart to double sampling plans. This procedure offers better statistical efficiency (in...
190 citations
TL;DR: The purpose of this paper is to propose a new control chart, the double sampling X chart, which is the counterpart to double sampling plans, which offers better statistical efficiency.
Abstract: The purpose of this paper is to propose a new control chart, the double sampling X chart, which is the counterpart to double sampling plans. This procedure offers better statistical efficiency (in...
186 citations
TL;DR: In this article, the authors suggest a new method to monitor the coefficient of variation (CV), a quality characteristic that has several applications in applied statistics and is receiving increasing attention in quality control.
Abstract: The coefficient of variation (CV) is a quality characteristic that has several applications in applied statistics and is receiving increasing attention in quality control. This paper suggests a new method to monitor the CV.
156 citations
Journal Article•
TL;DR: In this paper, a chart is proposed that is similar to the S chart and uses rational groups of observations for monitoring the coefficient of variation, rather than the variance, must be constant.
Abstract: When monitoring variability in statistical process control, conventional Shewhart R and S charts are used where the in-control readings have a constant variance. These charts cannot be used, however, in certain instances when the coefficient of variation, rather than the variance, must be constant. A chart is proposed that is similar to the S chart and uses rational groups of observations for monitoring the coefficient of variation.
129 citations