• 100% Satisfaction Guarantee
F. Naz, Chartered Accountant
Category: Homework
Satisfied Customers: 5314
Experience:  Experience with chartered accountancy
20040807
F. Naz is online now

# Need some help with a PERT/CPM problem. I have a table and

<p>Need some help with a PERT/CPM problem. I have a table and the Given/Task scenario I attached a link to get the files, it would not fit into the question box due to charactor length. Table 1.1 in the attached worksheet “PERT/CPM Tables” shows three estimates of the time it will take Company A to complete each of the activities and project tasks in the customer-feedback system project (optimistic, probable, pessimistic).</p><p>2 ATTACHEMENTS:  <a href="http://www.mediafire.com/file/2niwg5rkx1d/Task%2520309.3.2-01-06.pdf">http://www.mediafire.com/file/2niwg5rkx1d/Task%2520309.3.2-01-06.pdf</a></p><p>http://www.mediafire.com/file/cuzdwttztjk/309_3_2-01-06_PERT_CPM_Tables_TSRPF_(2)(1).xls</p>
Customer: replied 6 years ago.

Please revise? Calculations are a little off, below are the problems with the problem, but I can't figure out what the error is.

A2. PERT Chart

The PERT is correct. However, the critical path is not shown.

A4. Probability of Completing on Time

The work shown thus far is correct, but this is not the final result. Please reconsider final step(s).

C1. Activities to Be Crashed

Two of the tasks listed in this response are correct. Which two?

C2. Number of Weeks to Crash

Please revise based on the corrections to C1.

D. Least Increase in Cost

Though the response of 8834 is technically correct, the work shown does not support this response. Please revise once C1 and C2 are corrected and place close attention to units of measure.

You need to spend \$3 to view this post. Add Funds to your account and buy credits.
Customer: replied 6 years ago.
<p>VERY close, everything else factors correctly, but there is one minor detail that needs correction in the Probability of Completing on Time section, I got this feedback:</p><p>"The .0793 or 7.93% achieved is correct. However, this must be added to something else to achieve the correct probability. Please reconsider."</p><p>I am not sure exactly what they are referring to, was hoping you might know.  Not sure if it is a terminology thing or what.  </p><p> </p><p>Thank you SO much for helping me with this! I will gladly pay for another full amount when complete. I could never have figured this one out without you.</p>

I am sure that the 0.5 to be used, but not sure whether to add or subtract .0793 from 0.5.

Customer: replied 6 years ago.

My mentor gave me an example. He said the .0793 or 7.93% is correct, it is something else.....

Calculating probability of completion by week Y

Steps,

• 1. Determine week Y (the week targeted for completion).
• 2. Find your expected time to completion from the critical path, E(T).
• 3. Calculate your variances for each activity, 12Ïƒi2' type="#_x0000_t75">where i = activity A, B, C, etc..
• 4. Calculate variance for critical path from steps 3, 12Ïƒ2=ÏƒA2+ÏƒC2+ÏƒF2+ÏƒG2+ÏƒM2' type="#_x0000_t75">. Assuming A, C, F, G, M is the critical path.
• 5. Calculate standard deviation, 12Ïƒ=Ïƒ2' type="#_x0000_t75">, from step 4.
• 6. Calculate z statistic from steps 1, 2, and 5. 12z= Y-E(T)Ïƒ' type="#_x0000_t75">
• 7. Find probability in standard normal table.
• a. Note, in this standard normal distribution table the z stat provides the probability between Y and E(T) and therefore needs to have the probability of completion being less than E(T) (= 0.5)added.
• b. Note, in this standard normal distribution table, the probability that completion time will be less than Y is given.

Example.

Consider a project that has a critical path of A, F, H, K and an expected time, E(T) = 20 weeks.

The variances for each activity are: 12ÏƒA2=1.5;ÏƒF2=2.25;ÏƒH2=1.25;ÏƒK2=4' type="#_x0000_t75">.

Your boss wants you to calculate the probability the project will be complete in Y = 24 weeks.

• 1. Week Y = 24
• 2. E(T) = 20
• 3. 12ÏƒA2=1.5;ÏƒF2=2.25;ÏƒH2=1.25;ÏƒK2=4' type="#_x0000_t75">.
• 4. 12Ïƒ2=ÏƒA2+ÏƒF2+ÏƒH2+ÏƒK2=1.5+2.25+1.25+4=9' type="#_x0000_t75">
• 5. 12Ïƒ=Ïƒ2=9=3' type="#_x0000_t75">
• 6. 12z= 24-203=1.333' type="#_x0000_t75">
• 7. Probability of completion
• a. P(z ≤ 1.33) = .9082 or approximately 91%

I am lost, was hoping it might make sense to you.

It means that we should add .5 to .0793 to make it .5793 it means that probability is around 58%
Customer: replied 6 years ago.

Wondering if you might be willing to look at this problem and let me know if you could do it for me. I was thinking \$100.00?

I didn't want to post it for just anyone and was hoping it might be something you would do. Let me know if you are interested and if so, do I need to post it or do it through here or............