Monitoring the Ratio of Two Normal Variables Based on Triple Exponentially Weighted Moving Average Control Charts with Fixed and Variable Sampling Intervals

In statistical process control (SPC), the ratio of two normal random variables (RZ) is a valuable indicator to be taken as charting statistic. this work, we propose triple exponentially weighted moving average (TEWMA) chart for monitoring RZ. Additionally, variable sampling interval (VSI) strategy has been adopted different charts by researchers. With application strategy, VSI-TEWMA-RZ then developed further improve performance proposed TEWMA-RZ chart. The run length (RL) properties and are obtained widely used Monte-Carlo (MC) simulations. Through comparisons with VSI-EWMA-RZ VSI-DEWMA-RZ charts, statistically more sensitive than in detecting small moderate shifts. Moreover, it turned out that better on whole. Furthermore, paper illustrates implementation an example from food industry.