Free PMI Project Management Professional (PMP) Practice Question

The correct answer is 2 days. The standard deviation in PERT (Program Evaluation and Review Technique) is calculated using the formula: σ = (Pessimistic - Optimistic) / 6. In this case, we have:

σ = (22 - 10) / 6 = 12 / 6 = 2 days

This calculation is important because it helps project managers understand the variability in their estimates. A higher standard deviation indicates more uncertainty in the activity duration. In this case, a standard deviation of 2 days suggests a moderate level of uncertainty in the estimate.

The other answers are incorrect because they either use the wrong formula or misapply the given information. For example, 4 days would result from not dividing by 6, while 1 day and 3 days are arbitrary values that don't correspond to the correct calculation.