Beta distribution or Triangular distribution - what is the recommended method to use when estimating using PERT on the CAPM exam?

Fridaws Salisu IT Support Manager| Tek Experts Lagos, LA, Nigeria

What is the recommended formula to use when answering PERT related questions on the CAPM exam, beta or triangular distribution method?

Posted: Jan 27, 2025 3:58 AM

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Rami Kaibni

Community Champion

Senior Projects Manager | Field & Marten Associates New Westminster, British Columbia, Canada

Firdaws, it all depends on question and the details. Generally speaking, the Beta Distribution is the preferred formula since it’s more widely used in project management practice, especially in scenarios that involve uncertainty or variability in task durations as it will help you arrive at a more realistic estimate for your project’s activity durations.

If the question is vague and gives you the option to use any formula then I recommend you use the Beta Distribution: (O+4M+P)/6

Posted: Jan 27, 2025 10:52 AM

Keith Novak Tukwila, Wa, United States

If my memory is correct, the only 3-point estimation taught by PME is the special-case beta distribution formula provided by Rami. While the triangular distribution is the average of 3 estimates, the 4M provides a weighted average biased towards the Most Likely.

With respect to the underlying statistics, the beta distribution is preferred if the ML estimate is based on historical data. If a question states or implies that there is little or no historical data however, then that would make the triangular distribution a better choice.

Posted: Jan 27, 2025 5:51 PM

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Beta distribution or Triangular distribution - what is the recommended method to use when estimating using PERT on the CAPM exam?

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