Final answer:
The variance in the project completion time is the sum of the variances of all activities in the project.
Step-by-step explanation:
The statement is true.
In project management, the variance in the project completion time is calculated by summing up the variances of all the individual activities in the project. This approach is based on the assumption that the activities in a project are independent and have a known probability distribution.
For example, if Activity A has a variance of 4 and Activity B has a variance of 9, then the variance in the project completion time would be 13 (4 + 9).
Moreover, if two or more simultaneous activities are independent, their individual variances don't simply add up; the overall variance could be less than the sum of the individual variances. Correlations between task durations and uncertainties in task completion can further complicate the total variance calculation.