The hourly number of emergency telephone calls coming in to a police command and control centre has approximately a Normal distribution with mean of 130 and standard deviation of 25.
a) Assuming that calls arrive evenly throughout any hour and that one operator can deal with 24 calls in an hour, what is the probability that 6 operators will be able to deal with all the calls that arise in an hour? (30 marks)
b) Making the same assumptions as in (a), how many operators should there be to ensure that there is sufficient capacity to meet 95% of demand? (30 marks)
c) One possible scheme for increasing the efficiency of command and control centres is to combine the work of two such centres into one centre. For example, suppose a second centre has a similar workload to the one described above.
(i) Assuming that calls to the combined centre arrive evenly throughout any hour and that one operator can still deal with 24 calls in an hour, what is the probability that 12 operators will be able to deal with all the calls that arise in an hour? (20 marks)
(ii) Making the same assumptions again, how many operators should there be in the combined centre to ensure sufficient capacity to meet 95% of demand? (20 marks)
