To get this estimate, they decided to develop a simulation model because they were studying simulation in one of their classes at State. To develop a simulation model, they first needed to know how frequently the copier might break down— specifically, the time between breakdowns. No one could provide them with an exact probability distribution, but from talking to staff members in the college of business, James estimated that the time between break-downs was probably between 0 and 6 weeks, with the probability increasing the longer the copier went without breaking down. Thus, the probability distribution of breakdowns generally looked like the following:
0 6 x, weeks Next, they needed to know how long it would take to get the copier repaired when it broke down. They had a service contract with the dealer that “guaranteed” prompt repair service. However, Terri gathered some data from the college of business from which she developed the following probability distribution of repair times:
Repair Time (days) Probability 1 .20 2 .45 3 .25 4 .10
Finally, they needed to estimate how much business they would lose while the copier was waiting for repair. The three of them had only a vague idea of how much business they would do but finally estimated that they would sell between 2,000 and 8,000 copies per day at $ 0.10 per copy.