PERT Calculation

PERT distribution assumes a "Beta" probability distribution

Calculation produces an "Expected time" Te
- Where Te = (To+4Tm+Tp)/6
- That is to say, the Mean Value of the three estimates
And Standard Deviation
- St = (Tp-To)/6 (approx.)
The mean value is typically higher than the average value
- Because most activities take more time rather than less
- A sophisticated way of justifying a longer schedule
- (For more information on PERT, see Issacon #1112c, p5)