Activity	Immediate Predecessors	Optimistic Time	Most Likely Time	Pessimistic Time
a	none	4	6	7
b	a	1	2	3
c	a	5	5	5
d	b	7	9	12
e	b	2	4	8
f	c, d	6	9	10

1. What is the standard deviation of the critical path?

2. what is the expected duration of the critical path?

3. What is the probability that the project will take longer than 28 weeks to complete?

4. What is the expected duration of Activity A?

5. What is the expected variance of Activity A?