Control chart for x bar is maintained on a quality characteristic which is normally distributed.
The sample size is n=4. Consider one-sigma warning limits for this chart. Instead of typical rules for control charts, the company has decided to use only the following rule; if at least two of three consecutive points are greater than upper warning limit ( UWL = mu + alpha) or at least two of three consecutive points are less than lower warning limit ( LWL = mu - alpha), the process will be considered out of control. What is the ARL for the in-control process?