Some Results Concerning the Estimation of Beta Distribution Parameters in PERT

Abstract

The traditional method of estimating mean activity-time in PERT analysis, as a weighted average of the pessimistic, most likely and optimistic activity-times, is examined. Based on properties of the beta distribution, it is shown that there are theoretical grounds for using this estimate for a specified range of modal activity times. Finally, a simple refinement of the estimate is suggested when the modal value lies outside this range.

Keywords:

• PERT
• scheduling
• statistics