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***NOT INTERESTED IN PRIVATE TUTORS*** Only willing to work with Chegg members and deem points credit to those who can help through Chegg only.
***(Please show work - No longer rating or offering points unless work can be proven and correct.) Tired of paying for additional chegg points and receiving wrong answers and folks are just guessing so that can get rated and rewarded points.**
Given a simple Project like the one pictured above. Optimistic / Most Likely / Pessimist Times were assessed and Path Means and Path Standard Deviations were calculated. For Path 1-2-5 we have a Path Mean = 31 and a Path Standard Deviation = 4. For Path 1-3-4-5 we have a Path Mean = 30 and a Path Standard Deviation = 2. Determine both the Probability that Path 1-2-5 will finish in 31 Days or Less and the Probability that the Project will finish in 31 Days or Less. 0.977249938 : 0.977246615 0.5 : 0.345731234 0.77337272 : 0.755778443 0.987775567 : 0.987775283 0.977249938 : 0.977246615 0.5 : 0.345731234 0.77337272 : 0.755778443 0.987775567 : 0.987775283 0.977249938 : 0.977246615 0.5 : 0.345731234 0.77337272 : 0.755778443 0.987775567 : 0.987775283 Given a simple Project like the one pictured above. Optimistic / Most Likely / Pessimist times were assessed and Path Means and Path Standard Deviations were calculated. For Path 1-2-5 we have a Path Mean = 31 and a Path Standard Deviation = 4. For Path 1-3-4-5 we have a Path Mean = 30 and a Path Standard Deviation = 2. Determine both the Probability that Path 1-2-5 will finish in 31 Days or Less and the Probability that the Project will finish in 31 Days or Less. 0.977249938 : 0.977246615 0.5 : 0.345731234 0.77337272 : 0.755778443 0.987775567 : 0.987775283

Explanation / Answer

Let Z be a normal random variable with mean mu and std. dev. of sigma. Consider a transformation: X = (Z - mu)/sigma. Then X is a standard normal random variable with a mean of 0 and std. deviation of 1.

So, for path 1-2-5 : P(Z < 31) = P(X < (31 - 31) / 4) = P(X < 0) = 0.5

P(Project completed in 31 days) = P(path 1-2-5 finishes in 31 days) + P(1-3-4-5 finishes in 31 days) - P(both finish in 31 days). Like previous case: P(1-3-4-5 finishes in 31 days) = 0.6915. So,

P(Project completed in 31 days) = 0.8457

So, by narrowing down the options only second one is correct.

NOTE: It is not clear that what all paths are needed to complete the project, so the second answer is tentative

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