This Project Plan Template has a built in calculation for Expected Time using the Program Evaluation and Review Technique, or PERT.
A full PERT Project Plan template would include additional components such as the critical path definition, a Gantt Chart, etc. Other tools, such as Microsoft Project, are preferred over Excel for that type of work. This PERT template is intended to incorporate the Expected Time calculation from the PERT Project Management method.
Expected Time is calculated based on three different estimates of time for a single task of work. The first estimate is the Optimistic Time, or the minimum amount of time to complete the task. It assumes everything proceeds better than is normally expected. The next estimate is the Pessimistic Time. This is the maximum amount of time required to complete the task and assumes that many things go wrong. The final estimate is the Most Likely Time. This is the best estimate of time to complete the task and assumes that everything proceeds as normal.
The Expected Time is then calculated by multiplying the Most Likely Time by four, then adding the Pessimistic Time and the Optimistic Time and dividing the entire sum by six. This takes into account all three estimates provided, but weights the Most Likely Time the heaviest.