Explanation: It is useful to present a graphical display for the tabular cusum. These charts are sometimes called the cusum status charts.

Explanation: Cusum status charts are constructed by plotting Ci+ or Ci– versus the sample number. These are used to get an quick information about the process from the displayed chart.

Explanation: Cusum status charts are the charts made to represent the cusum data on a graphical display, where each vertical bar in the cusum status charts, represents the value of Ci+ and Ci–.

Explanation: The value of the decision interval H can be used as the control limits in the cusum charts as in the Shewhart charts. This gives us an indication about when the process is out-of-control.

\(C_i^-=min⁡\left\{0,x_i-μ_0+k+C_{i-1}^-\right\}\).

Explanation: The Minitab version of the tabular cusum uses the negative expression for the Ci–, so the value of Ci– always remains less than or equal to zero.

Explanation: When an out-of-control situation is encountered while using the cusum control charts, we use the same procedure, used as in the Shewhart control charts. First, identifying the assignable cause, then second, taking corrective action, and then restarting the control chart from zero.

Explanation: As the pattern changes in the cusums due to an assignable cause, the changed pattern gets recorded in all the next cusums. So, we can identify from which cusum, the pattern changed, and hence the assignable cause location can be known.

\(\hat{μ}=\left\{μ_0+K+\frac{C_i^+}{N^+}\right\}\)