PERT Analysis MCQ with answer and solution

Concept

Beta Distribution in PERT Analysis

Formula

Expected time (te) = (a + 4m + b) / 6, where a = optimistic time, m = most likely time, and b = pessimistic time.

Step-by-step solution

Identify the optimistic time (a), most likely time (m), and pessimistic time (b) for the activity, then plug these values into the formula te = (a + 4m + b) / 6 to calculate the expected completion time modeled by the Beta distribution.

Explanation

In PERT analysis, individual activity completion times are uncertain and modeled using a Beta distribution. This distribution is ideal because it is defined over a fixed interval between the optimistic and pessimistic time estimates and can accommodate asymmetric or skewed distributions to reflect realistic task variability.

Shortcut

Remember "Peanut Butter": PERT uses Beta distribution for activity duration.

Common mistake

A common mistake students make is confusing the probability distribution of an *individual activity duration* with the distribution of the *overall project completion time*. Students often select **Option B (Normal distribution)** because the total project duration in PERT follows a normal distribution according to the Central Limit Theorem. However, the duration of an *individual activity* follows a Beta distribution (Option C).