A new exponentially weighted moving average sign chart using repetitive sampling

• A new nonparametric control chart based on EWMA sign statistic is proposed.
• The control chart is proposed to effectively detect the process shift away from the target value.
• The proposed control is based on two pairs of upper and lower control limits.
• The ARLs of the proposed control chart are evaluated through the Monte Carlo simulation.
• The proposed control chart is shown to be more efficient than the existing EWMA sign control chart.

In this paper, a new nonparametric control chart based on the exponentially weighted moving average (EWMA) sign statistic is proposed using repetitive sampling. The control chart is proposed to effectively detect the process mean shift away from the target value without the distributional assumption on the quality characteristic. The proposed control chart is based on two pairs of upper and lower control limits having different control coefficients. The in-control and the out-of-control average run lengths of the proposed control chart are evaluated through the Monte Carlo simulation. The proposed control chart is shown to be more efficient than the existing EWMA sign control chart in terms of the average run length.