A small sample of your project’s PERT calculations is presented here. Activity 2 is particularly essential to the project, and your stakeholders are requesting a confidence level for this activity. You tell them there is a 95.44 percent chance of finishing activity 2 within how many days?
First, you need to calculate the standard deviation for this activity, which is 1.67. That is, (Pessimistic – Optimistic) ÷ 6. A 95.44 percent confidence factor is 3 standard deviations. That is, 1.67 × 3 = 5.01. The expected value is 23 days, so you have a 95.44 percent chance of completing the activity within between 18 and 28 days.