Six Sigma Green Belt Certification Practice Exam

Using the critical path method (CPM), how can you determine if an activity is on the critical path?

1. The activity's earliest and latest times of completion are the same

2. The activity's slack time is less than the time required to complete the activity

3. The activity's latest time of completion is larger than its earliest time of completion

4. The activity's slack time is more than the time required to complete the activity

The correct answer is: The activity's earliest and latest times of completion are the same

The critical path method (CPM) is a project management tool used to determine the sequence of activities that directly affects the project's duration. An activity is considered to be on the critical path when there is no flexibility in its timing. This is measured by the earliest and latest times of completion for that activity being the same, which implies that any delay in this activity will directly result in a delay of the overall project. When the earliest and latest completion times for an activity align, it indicates that there is zero slack time or float available; hence, this activity is crucial for maintaining the project schedule. If any changes occur in the timing of that activity, it would impact the project's completion date. The other options describe scenarios that do not indicate that an activity is on the critical path. If an activity's slack time is less than the time required for its completion, it could potentially still have slack; hence, it doesn't necessarily mean it's critical. Having a latest time of completion larger than the earliest time does not directly indicate criticality because it might still include slack. Likewise, if an activity's slack time is greater than the time required to complete the activity, it suggests that there is flexibility in scheduling that activity, which rules it out as being critical