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# Project Management Central

 If the output calculation of Beta disrtribution and traingluar for three -point estimate have the SAME RESULT , is this indicate somthing for you?   A) BETA DISTRIBUTION(weighted average=PERT) = (P+4(ML)+O)/6 B) TRIANGULAR (simple average) = (P+M+O)/3 some times it called linear (and calculated when there is NO risk). If you take the O=10 days, P=16 days and M=13 days The result in both A and B =13 I am asking this question because (sometimes not mentioned in the context if there is ( risk/no-risk) / nor (triangular/beta) ,so in this case I should calculate both of them and see if result match one of the answers. BR, Posted: Mar 26, 2020 12:57 PM   Mansour -

In general, if the distribution is not specified, go with the Beta distribution on the exam.

It is perfectly normal that the two distributions will provide the same answer if you have pessimistic and optimistic values which are equidistant from the most likely.

Kiron   Mansour,

the values are determined by the equation M = (P+O)/2, which is the same as Kiron mentioned with equidistance from the most likely M, which then is also the mean.

Thomas   As somebody training into statistics (one of my grades are "licenciado en estadística" which I think is the same than bachelor major on statistics) my recommendations is going to the definition of the function that best caracterized the activity distribution. And let me say: if you are using things like PERT it has no sense to spend too much time on this. To justify or understand that go to for PERT definition mainly why the normal distribution is the best approach to take taking into account the inherent errors.   