If a project is expected to be completed in 68 days with a project variance of 21 days,what is the probability that the project will be completed within 90 days?
A)between 5% and 10%
B)between 15% and 20%
C)between 25% and 30%
D)none of these

Question

Quizplus · Accepted Answer

To find the probability that the project will be completed within 90 days, we use the formula for the Z-score: Z = (X - μ) / σ, where X is the target completion time (90 days), μ is the mean project duration (68 days), and σ is the standard deviation. The project variance is 21 days, so the standard deviation is the square root of the variance, which is √21 ≈ 4.58 days. Plugging into the formula gives Z = (90 - 68) / 4.58 ≈ 4.80. This Z-score corresponds to a probability that is not directly listed in the options, indicating that the actual probability is very high and not within the provided ranges. Therefore, the correct answer is "none of these."

If a Project Is Expected to Be Completed in 68