Question

the duration of a certain physical process

Answer 1

Answer:

If process duration distributions are exponential or general gamma, a reasonable assumption, then the response time can be derived from an order-of-processing (OP) diagram (Fisher and Goldstein 1983).  the OP diagram for a PERT network in which processes a and b are concurrent and both are followed by process c. Each vertex in the OP diagram is a state, in which certain processes are under way (upper list) and certain others are completed (lower list). The task begins with a and b both under way. In the following states, either a is completed first or b is completed first. Following either of these states, process c is under way. In the final state, process c is completed, and the task is finished.