Question

Can someone answer this for me please?

Given the accompanying network diagram, with times shown in days. Use Table B1 and Table 82 7-8-10 7.8:10 - a. Determine the expected duration of the project. (Round intermediate calculations to 2 decimal places and final answer to 1 decimal place.) Expected Duration b. Compute the probability that the project will take at least 18 days. (Round intermediate calculations to 2 decimal places and "Probability" values to 4 decimal places.) Probability

Answer 1

Answer a=

Activity	Optimistic	Most Probable	Pessimistic	Expected completion time	Expected compleetion time	variance
1-2	4	5	6	(4+4*5+6)/6	5.00	0.11
2-4	7	8	10	(7+4*8+10)/6	8.17	0.25
1-3	7	8	11	(7+4*8+11)/6	8.33	0.44
3-5	2	3	4	(2+4*3+4)/6	3.00	0.11
4-6	3	5	9	(3+4*5+9)/6	5.33	1.00
5-6	1	4	6	(1+4*4+6)/6	3.83	0.69
	Formula for Expected completion time = (O+4M+P)/6
	Variance = ((P-O)/6)^2

Answer a=

Different paths and their duration=

1-2-4-6=5+8.17+5.33 =18.5

1-3-5-6=8.33+3+3.83=15.16

So the project duration =18.5

Answer b=

Variance of critical path =0.11+0.25+1=1.36

Standard deviation = variance^0.5 =1.36^0.5 =1.17

Formula z=(X-M)/standard deviation

In the question,

X=desired completion time

M=actual completion time

In the given question,

X=18 days

M=18.5 days

Z=(18-18.5)/1.17 =-0.427

P(z) =0.3372

So the probability is 0.3372