Stephanie Robbins is the Three Hills Power Company management analyst assigned to simulate maintenance costs. In Section 14.6 we describe the simulation of 15 generator breakdowns and the repair times required when one repairperson is on duty per shift. The total simulated maintenance cost of the current system is $4,320.
Robbins would now like to examine the relative cost-effectiveness of adding one more worker per shift. The new repairperson would be paid $30 per hour, the same rate as the first is paid. The cost per breakdown hour is still $75. Robbins makes one vital assumption as she begins-that repair times with two workers will be exactly one-half the times required with only one repairperson on duty per shift. Table 14.13 can then be restated as follows:
REPAIR TIME REQUIRED (HOURS) PROBABILITY
0.5 â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦ 0.28
1 â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦ 0.52
1.5 â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦â€¦ 0.20
(a) Simulate this proposed maintenance system change over a 15-generator breakdown period. Select the random numbers needed for time between breakdowns from the second-from-the-bottom row of Table 14.4 (beginning with the digits 69). Select random numbers for generator repair times from the last row of the table (beginning with 37).
(b) Should Three Hills add a second repairperson eachshift?