12.51 Implications of out-of-control signal.
For attribute control charts, explain the difference in implications for a process and in actions to be taken when the plotted statistic falls beyond the upper control limit versus beyond the lower control limit.
12.51
Usually with attribute control charts, we are keeping track of count data that have a negative aspect, such as the number of mistakes. So, if we get an out-of-control point above the UCL, we want to find the source of special cause and try to correct it. However, if we get an out-of-control point below the LCL, we want to find the source of the special cause and mimic it in the future to potentially change (reduce) the level of the process.