PMI-SP Duration Estimating 5 — Questions and Answers
Question 1: A project uses parametric estimating and historical data shows an average cost of $500 and a duration of 3 days per deliverable unit. If the project scope includes 40 units, what is the estimated total duration?
- 40 days
- 80 days
- 120 days (Correct answer)
- 160 days
Correct answer: 120 days
Total duration = 3 days/unit × 40 units = 120 days using the parametric estimating formula.
Question 2: A project scheduler is documenting the basis of estimates. Which information is MOST important to capture in this document?
- The final approved schedule baseline
- The sources, assumptions, constraints, and confidence level of each estimate (Correct answer)
- The names of team members who provided estimates
- The cost associated with each activity duration
Correct answer: The sources, assumptions, constraints, and confidence level of each estimate
The basis of estimates documents the sources of data, assumptions made, constraints considered, and confidence levels to support transparency and future auditing.
Question 3: During a planning session, the team debates whether to use expert judgment or parametric estimating. The project involves a novel technology with no historical performance data. Which technique should be selected?
- Parametric estimating, using industry benchmarks
- Expert judgment from experienced SMEs in the technology domain (Correct answer)
- Analogous estimating from a completely different technology project
- Automated estimation software with default settings
Correct answer: Expert judgment from experienced SMEs in the technology domain
When no historical data exists for a novel technology, expert judgment from domain SMEs is the most reliable estimating technique.
Question 4: A PMI-SP professional is analyzing a schedule where activity durations were estimated without considering the law of diminishing returns. What risk does this create?
- Activity costs will be underestimated
- Adding resources later will not reduce the schedule as expected (Correct answer)
- The critical path will become shorter than estimated
- Risk reserves will be overfunded
Correct answer: Adding resources later will not reduce the schedule as expected
Ignoring diminishing returns means the team may expect linear duration reductions from added resources, but actual results will underperform expectations.
Question 5: Which of the following scenarios represents the CORRECT application of lag in the context of duration estimating and schedule development?
- Starting activity B two days before activity A finishes
- Waiting 5 days after concrete is poured before beginning the next phase (Correct answer)
- Compressing activity durations to shorten the project
- Adding buffer time at the end of the project schedule
Correct answer: Waiting 5 days after concrete is poured before beginning the next phase
Lag represents a required waiting period between dependent activities, such as curing time after pouring concrete before the next activity can start.
Question 6: A project's duration estimate uses a triangular distribution instead of a beta distribution. How does the triangular distribution treat the most likely estimate compared to PERT?
- It weights the most likely estimate four times more than PERT
- It gives equal weight to all three estimates (Correct answer)
- It ignores the pessimistic estimate
- It applies only to activities on the critical path
Correct answer: It gives equal weight to all three estimates
The triangular distribution formula (O + M + P) / 3 gives equal weight to all three estimates, unlike PERT which weights the most likely estimate four times.
Question 7: A project manager wants to express the range of uncertainty in duration estimates. The PERT expected duration is 15 days and the standard deviation is 2 days. What is the range representing a 68% confidence interval?
- 11 to 19 days
- 13 to 17 days (Correct answer)
- 9 to 21 days
- 15 to 17 days
Correct answer: 13 to 17 days
A 68% confidence interval equals ±1 standard deviation: 15 ± 2 = 13 to 17 days.
PMI-SP Duration Estimating 5
A project uses parametric estimating and historical data shows an average cost of $500 and a duration of 3 days per deliverable unit.
If the project scope includes 40 units, what is the estimated total duration?