CAPM Practice: Demonstrate an understanding of a project management plan schedule

Three-point estimates (optimistic, most likely, pessimistic) are used when activity durations are uncertain. They account for schedule risk by incorporating best-case and worst-case scenarios. Single-point estimates assume certainty; three-point estimates acknowledge and quantify uncertainty, producing more reliable estimates through PERT or triangular distribution formulas.

**Why not B:** When activities are completely certain and risk-free, single-point estimates are sufficient because there is no variability to account for. Three-point estimates add value precisely when uncertainty exists, making the optimistic and pessimistic bounds meaningful.

**Why not C:** Three-point estimates are valuable for any activity with duration uncertainty, not just those on the critical path. Near-critical activities and activities with high variability also benefit from three-point estimation to capture schedule risk across the entire project.

**Why not D:** Three-point estimates are appropriate whenever uncertainty exists, regardless of the project manager's experience. Even experienced project managers benefit from capturing the range of possible outcomes. The technique addresses activity uncertainty, not the estimator's familiarity with the work.