An economic design of combined double sampling and variable sampling interval X¯ control chart

A combination of double sampling X¯ chart and variable sampling intervals X¯ chart (DSVSI) can successfully reduce the detection time of small mean shift. Before a DSVSI X¯ chart is used, its design parameters should be determined. This study constructs an economic design model of DSVSI X¯ chart for the determination of the design parameters. Then, the Genetic Algorithms (GA) are used to solve the optimal designs of DSVSI X¯ chart. Finally, a numerical example is provided to illustrate the use of this model. A sensitivity analysis of the effects of model parameters on the optimal design of DSVSI X¯ chart is also performed.