TOPIC: Questions regarding information from PMBOK

Hello, in my studies of PMBOK I noticed a something that I need help with.

In section 11.4.2.2 there is a section "Modelling and Simulation" which has a figure 11.17, using data from Figure 11.13. I understand the concept of how this works, what I don't get is how they arrive at 12%, the formula for the "y" value on cumulative curve with the mode (most likely result) being known is, (c-a)/b-a), which in this case equals 0.27 .

Please can someone help clarify this for me?

Nicholas,

Good question. I took a look at this and also do not see how they get 12%. Even if I estimate the values for a and b where the curves end as 34.375 and 60.625 respectively I get 25%. It isn't clear what values they are actually using for b and a. Sorry I couldn't be of more help.

Mark

Thank you very much for having a look at least