The PERT estimate E is based on a formula that includes your optimistic time estimate O your most likely time estimate M and your pessimistic time estimate P. The default value for this parameter is 4. The PERT Formula is most commonly used in project management for estimating project durations.
Pert A p e r t A Divide each term by ert e r t and simplify.
An optimistic estimate the most likely estimate and a pessimistic estimate. In the PERT Entry dialog box type a number for the Optimistic Expected and Pessimistic durations. PERT formulas The regular three-point estimate is simply the average of the pessimistic P most likely M and optimistic O estimates or P M O3 PERT analysis takes the weighted average which gives 4 times as much weight to the most likely or M estimate. In the PERT distribution the mean m is calculated mu frac x_min x_max lambda x_mode lambda 2.