The expected time $$\left( {{t_e}} \right)$$ of a $$PERT$$ activity in terms of optimistic time $$\left( {{t_0}} \right)$$, pessimistic $$\left( {{t_p}} \right)$$ and most likely time $$\left( {{t_L}} \right)$$ is given by

Consider the following network

The optimistic time, most likely time and pessimistic time of all the activities are given in the table below :

The critical path duration of the network (in days) is

Consider the following network

The optimistic time, most likely time and pessimistic time of all the activities are given in the table below :

The standard deviation of the critical path is

Which of the following forecasting methods takes a fraction of forecast error into account for the next period forecast?