Figure 12
The first chart, an Individual Value chart, shows data points fluctuating around a center line at 8.04. The upper control limit is at 16.86, and the lower control limit is at -0.79. The second chart, a Moving Range chart, shows data points fluctuating around a center line at 3.32. The upper control limit is at 10.84, and the lower control limit is at 0. Both charts share an observation x-axis from 1 to 181. The process is in control despite some elements outside the limits.Control chart for total service time after the improvements. Source: Authors' own creation