From the HIV/AIDS incidences data in Table 2, CUSUM statistic signal out-of-control at period 8 i.e August 2001 since > H=70. Thus at this period an assignable cause of variation is at work but which gradually fizzle out from period 23 because less patients tested positive to this disease from November 2002 probably as a result of awareness and government intervention which reduces the rate of infection . Also, the superiority of the CUSUM chart over the Shewhart chart for monitoring a small sudden shift in process variable is shown in Table 3. The Cusum chart is able to quickly detect an out-of-control (abnormal) condition for the number of HIV/AIDS patient than the Shewhart chart