CMA Final · Strategic Cost Management · Network Analysis - PERT, CPM
For a PERT activity, the optimistic time is 4 days, the most likely time is 7 days and the pessimistic time is 16 days. What is the expected time of the activity under the beta distribution assumption?
The expected time is 8 days. PERT weights the most likely time four times, so (4 + 4×7 + 16)/6 equals 8. A simple average of the three estimates gives 9 days, which is not the PERT method.
- A7 days
- B8 daysCorrect
- C9 days
- D10 days
Explanation
Expected time = (a + 4m + b)/6 = (4 + 28 + 16)/6 = 48/6 = 8 days. The 9 days option comes from a simple average (4+7+16)/3, which ignores the 1-4-1 weighting that PERT uses.
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