In the sample data table Clips1.jmp, the measure of interest is the gap between the ends of manufactured metal clips. To monitor the process for a change in the average gap, subgroup samples of five clips are selected daily.
1. Select Help > Sample Data Library and open Quality Control/Clips1.jmp.
2. Select Analyze > Quality and Process > Control Chart > EWMA Control Chart.
3. Select Gap and click Y.
4. Select Sample and click Subgroup.
5. Click OK.
Figure 9.2 EWMA Control ChartÂ
Purple vertical lines in the EWMA chart denote shifts. Shift starts are detected at samples 4 and 17.