pmp ques bank ques


 


53. What is the expected value of the number of days to complete the project?
a. 47.3
b. 22.0
c. 32.3
d. 48


 


54. It is desirable to make an estimate that has a greater than 95% chance of being correct. Which of the following ranges of time for the impletion of the project best describes this probability of being correct?


a. 33.31 to 31.36
b. 34.28 to 30.39
c. 14.39 to 33.48
d. 35.25 to 29.42


ans c & b


im sorry, i couldnt paste the picture here so have given a link.


can anybody help me in solving these ques.



http://sites.google.com/site/pmpbank/5356.jpg
In a project to install concrete sewer lines there is a lot of uncertainty as to how long the durations should be for the tasks involved. The project manager has determined that the team will use the PERT technique to evaluate the project’s completion date. The diagram shows nine
activities and the table shows the optimistic, pessimistic, and most likely estimates that the team has already made 

Ans:53


option C- 


You need to find out critical path for each possibility and calculate total number of days to complete project. Then find out EV by formula - (O+P+4M)/6.


 


O=28


P=38


M=32


Ans:54


Option B- Find out values of EV,SD and activity variance of each activity on critical path. Sum up acitivity variance and take square root of the same. it is SD for project. To find out range ot time of completion for 95% is 2SD.


i,e. ED+2sd and ED-2sd


ans  is 34.28 and 30.39


Formulas - EV is as above


SD= (p-o)/6


Variance - (P-O)/6 *(P-O)/6


thanks


Raj


 


 

thanks raj,


after reading ur soln i could solve it. but still i have some doubts it would be grt if u clear them:


1. is the dig given in the ques is correct? from I 2 arrows are going to G & H. i thought it was wrong so changed the arrow directions(i.e from G & H both are now going into I)


2. how did u come to know that we have to calculate critical path in this? i have done some questions on PERT where i didn't find out critical path. i'm sure im missing some concept here.


thanks once again.


 

Critical path is longest duration of the project. Expected duration is required to calculate SD and ranges.


thanks