Final answer:
To have an 85 percent chance of completing a project by the due date, with a mean completion time of 100 weeks and standard deviation of 10 weeks, the due date should be set to 110.4 weeks. This is calculated using the Z-score for the 85th percentile, which is 1.04, applying the formula X = mean + (Z-score * standard deviation).
Step-by-step explanation:
To set a due date with an 85 percent chance that the project will be finished by this time, given a normal distribution with an expected completion time (mean) of 100 weeks and a standard deviation of 10 weeks, we need to use the concept of normal distribution and Z-scores.
First, we need to find the Z-score that corresponds to the 85th percentile. This is typically found using a Z-table or statistical software. The Z-score for the 85th percentile is approximately 1.04. Once we have the Z-score, we can use the formula:
X = μ + (Z * σ)
Where:
X = the due date
μ = the mean (expected completion time, which is 100 weeks)
Z = Z-score (which is 1.04 for the 85th percentile)
σ = the standard deviation (which is 10 weeks)
Now, substituting the values into the formula:
X = 100 + (1.04 * 10)
X = 100 + 10.4
X = 110.4 weeks
The due date should be set at 110.4 weeks to have an 85 percent chance of completing the project by this time.