The table given below shows the precedence relations, and three time estimates (optimistic, most likely, and pessimstic) of activities of a project. Write down the mean and standard deviation of the project completion time.

	Time (weeks)
Activity	Immediate Predecessor(s)	optimistic	most likely	pessimistic
A	-	1	2	3
B	A	3	5	7
C	A	2	4	12
D	B, C	4	5	12
E	B	3	4	11
F	B	1	3	5
G	C, D	3	4	5
H	E, F	2	3	4