## Exam Spotlight

For the exam, I recommend that you know that one standard deviation gives you a 68 percent (rounded) probability and two standard deviations gives you a 95 percent (rounded) probability. Also, know how to calculate the range of project duration dates based on the expected value and standard deviation calculation. You probably don't need to memorize how to calculate the standard deviation because most of the questions give you this information. You should, however, memorize the PERT formula and know how it works. It wouldn't hurt to memorize the standard deviation formula as wellâ€”you never know what might show up on the exam.

PERT is not used often today. When it is, it's used for very large, highly complex projects. However, PERT is a useful technique to determine project duration when your activity durations are uncertain. It's also useful for calculating the duration for individual tasks in your schedule that might be complex or risky. You might decide to use PERT for a handful of the activities (those with the highest amount of risk, for example) and use other techniques to determine duration for the remaining activities.