A small software development project has the following major activities. The estimates times are

provided below:

Activity Immediate Predecessor a m b

A $--258$

B A $369$

C A $4710$

D B $2514$

E D $333$

F C $6810$

G E$,$ F $111$

H C $61014$

I G$,$ H $345$

$4.$ What is the expected completion time for this project?

Answer:

$5.$ What variance would be used in finding probabilities of finishing the project by a certain time?