Mechanical Engineering - Industrial Engineering and Production Management - Discussion

Discussion Forum : Industrial Engineering and Production Management - Section 2 (Q.No. 6)
6.
A PERT network has three activities on critical path with mean time 3, 8 and 6 and standard deviations 1, 2 and 2 respectively. The probability that the project will be completed in 20 days is
0.50
0.66
0.84
0.95
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 1 of 3.

Yawer abbas said:   1 decade ago
how we calculate project completion time probability through mean time of critical activities and standard deviation eaxmple:

A PERT network has three activities on critical path with mean time 3, 8 and 6 and standard deviations 1, 2 and 2 respectively. The probability that the project will be completed in 20 days is.

Udita Jain said:   1 decade ago
Sigma = 3.
Te = 3+8+6 = 17.
(20-17)/3 = 1.

So probability = 84%.

Prakash patel said:   1 decade ago
What is sigma? Please explain briefly.

Sumit agrawal said:   1 decade ago
Tell me about this question in detail.

Axiss said:   1 decade ago
3+8+6/20 = 0.84.

Ramanathan said:   1 decade ago
What is the 20? Is it from formula?

Ashok kumar said:   1 decade ago
Sigma is standard deviation = Under root of 1^2+2^2+2^2 means it will 3.

Z = (t-te)/under root of variance.

Amal said:   10 years ago
Z = (ts-te)/sigma.
Where sigma = deviation, sqrt(variance).

Ts = 20 days.
Te = mean time = 3+8+6 = 17.

Sachin said:   10 years ago
(20-3-8-6)/(1^2+2^2+2^2)^1/2 = 1.

Jerrin said:   9 years ago
Then how it become 84%?


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