True$/$False $(1$ point each$)$

Productivity of a process can be measured by dividing its input by its output.

Slack is the amount of time an activity can be delayed without delaying the entire project.

The ES of an activity that has many predecessors is simply the EF of that predecessor.

The standard deviation of project duration is the average of the standard deviation of activities on the critical path.

The longest of all paths through the network is the critical path.