It is also desirable that a control chart is sampling rate be reasonable. A measure of the
average sampling rate can be constructed using the ANOS. As an example consider the X chart
with h=3. This control has an in-control ANOS of 370.4 observations. If the sampling interval
is two hours. then the in-control ATS is 740.8 hours and the average in-control sampling rate
is ANOS/ATS=370.4/740.8=0.5 observations per hour.