If a project has an expected completion time of 15 weeks with a variance of 4 weeks,the probability that the project will be completed in 18 weeks is ______.
A)less than 34%
B)between 44% and 68%
C)between 69% and 83%
D)more than 93%

Question

Quizplus · Accepted Answer

Using the standard normal distribution (Z = (X - μ) / σ), where X is the target time (18 weeks), μ is the mean (15 weeks), and σ is the standard deviation (√variance = √4 = 2 weeks), we find Z = (18 - 15) / 2 = 1.5. Looking up 1.5 in the Z-table gives a probability of about 93.32% that the project will be completed in 18 weeks or less, hence the probability is more than 93%.

If a Project Has an Expected Completion Time of 15