Its a weighted average. The 4 and 6 are related to each other in that you have 4 parts of one element and 1 part each of two other elements for 6 total parts. The equation could just as easily have 6/8 instead of 4/6 if the probable estimate was deemed to have a higher weight.
I do not know why 4/6 is generally used as opposed to 6/8, 10/12 or any other weighting factor.
I hope you understand and recall your mathematics or higher algebra, differential calculus, intergral calculus, engineering mathtmatics or any subject related to mathematics.
Cheers,
Charlie
Member for
23 years
Member for23 years
Submitted by Steven Oliver on Thu, 2006-04-13 04:18
Member for
20 years 1 monthRE: Why 6?
Its a weighted average. The 4 and 6 are related to each other in that you have 4 parts of one element and 1 part each of two other elements for 6 total parts. The equation could just as easily have 6/8 instead of 4/6 if the probable estimate was deemed to have a higher weight.
I do not know why 4/6 is generally used as opposed to 6/8, 10/12 or any other weighting factor.
Stacy
Project Management Knowledge Base
Member for
20 years 4 monthsRE: Why 6?
Hello,
This is related to the theory of probability.
The graph generated is a bell shape.
The equation is similar to mean average.
I hope you understand and recall your mathematics or higher algebra, differential calculus, intergral calculus, engineering mathtmatics or any subject related to mathematics.
Cheers,
Charlie
Member for
23 yearsRE: Why 6?
Where
a = pessimistic duration
4m = 4 * probable duration
b = optimistic duration
generally accepted "rule of thumb". You could equally propose your own method.
(((a+b)/2)+m)/2) for instance