A control chart consists of several parts ... the control plan direction for a UCL special cause. Use the UCL (Along with the LCL) to Evaluate the Predicted Spread of Common Cause Variation ...

p expected proportion of nonconforming items produced by the process The lower and upper control limits, LCL and UCL, respectively, are computed as A lower probability limit for p i can be determined ...

This assumes that the process is in statistical control and that X i is binomially distributed. The lower probability limit LCL is then calculated by setting and solving for LCL. Similarly, the upper ...