A project whose critical path has an estimated time of 820 days with a variance of 225 has a 20% chance that the project will be completed before which day (rounded to nearest day)?
A) 631
B) 689
C) 807
D) 833
E) 1009

Question

Quizplus · Accepted Answer

Using the formula for the Z score in project management, Z = (X - μ) / σ, where X is the desired time, μ is the mean (820 days), and σ is the standard deviation (the square root of the variance, which is √225 = 15). To find the day by which there is a 20% chance of completion, we look for the Z value corresponding to 20% in a Z-table, which is approximately -0.84. Plugging the values into the formula gives us -0.84 = (X - 820) / 15. Solving for X gives us X ≈ 807 days.

A Project Whose Critical Path Has an Estimated Time of 820