Which option satisfies the requirements for estimating expected activity times in a PERT network?

To accurately estimate expected activity times in a PERT (Program Evaluation Review Technique) network, utilizing three estimates is essential. PERT is designed to account for uncertainty in activity durations by calculating a weighted average of optimistic, pessimistic, and most likely time estimates.

The three estimates are as follows:

1. Optimistic Time (a): This represents the least amount of time required to complete the activity, assuming everything proceeds better than expected.

2. Pessimistic Time (b): This is the maximum amount of time the activity might take, assuming everything goes poorly.

3. Most Likely Time (m): This is the time required to complete the activity under normal conditions, reflecting a realistic view of the challenges involved.

By incorporating all three of these estimates, you can derive an expected time using the formula:

[ \text{Expected Time} = \frac{a + 4m + b}{6} ]

This formula gives more weight to the most likely estimate, which balances the impact of the more extreme optimistic and pessimistic estimates.

Using only two estimates does not capture the range of uncertainty effectively, and relying solely on the mean estimate overlooks the variability in activity durations. Emphasizing the least