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andytill/Probability of Project Success.md

Last active August 29, 2015 14:09
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Probability of Project Success
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Probability of Project Success.md

Quiz

There are ten tasks in a project and they all need to be completed within their estimate for the project to be delivered on time. Each task has a 10% chance that is mis-estimated and will take longer.

What is the probability that the project will be delivered on time?

If a task has a 10% chance of being late it has a 90% (0.9) probability of success. Probability of multiple events is calculated by multiplying all the probabilties: 0.9 * 0.9 * 0.9 etc. In the contrived example where all probabilites are the same we can do a simple power of:

Eshell V5.10.2  (abort with ^G)
1> math:pow(0.9, 10).
0.3486784401000001

The total probability of the project being delivered on is 34.8%, pretty bad eh?

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