ITPEC FE Morning April 2022 Question 54
When the triangular distribution formula in the three-point estimation technique is used, which of the following is the expected duration in days required for an activity? The estimates are as shown below.
Conditions – Estimates for the duration of the activity
Case 1: Two (2) days – if an experienced employee is assigned to this activity
Case 2: Four (4) days – if an average employee is assigned to this activity
Case 3: Twelve (12) days – if an inexperienced employee is assigned to this activity
Explanation
6 days — the triangular distribution weights the three estimates equally.
- •Optimistic O = 2, most likely M = 4, pessimistic P = 12
- •Expected duration: E = (O + M + P) ÷ 3 = (2 + 4 + 12) ÷ 3 = 18 ÷ 3 = 6
Answer (c)
Why not others:
- •(a) 4 — the most likely estimate alone, ignoring the other two
- •(b) 5 — the beta (PERT) formula (O + 4M + P) ÷ 6 = (2 + 16 + 12) ÷ 6 = 5, not the triangular one the question asks for
- •(d) 7 — (2 + 12) ÷ 2, the midpoint of the optimistic and pessimistic estimates, leaving out the most likely one
Key rule: The triangular estimate divides the plain sum by 3, while the beta (PERT) estimate weights the most likely value by 4 and divides by 6; check which distribution the question names.
Project Management · AI-written, may contain errors
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