Compute limits for the sample mean x $$ around $\backslash$mu $=12$ such that, as long as a new sample

mean is within those limits$,$ the process will be considered to be operating satisfactorily.

If x $$ exceeds the upper limit or if x $$ is below the lower limit$,$ corrective action will be taken.

These limits are referred to as upper and lower control limits for quality control purposes.