Beta Distribution


A beta distribution is similar to a triangular distribution in that it has the highest probability at the base, or mid-range, cost. However, a beta distribution falls away more rapidly from the peak than a triangular distribution.


Modelling a cost as $10,000 -10%/+20% with a beta distribution indicates a greater confidence in the mid-range of $10,000 than would a triangular distribution.


Using this distribution also indicates a belief that under no circumstances will the actual cost be outside the specified range.