Decision Making and Construction

Decision Making and Planning in Construction The formula to determine the most probable to complete the backyard swimming pool is as follows: Where a = Optimistic m = Most probable b =Pessimistic The study uses Microsoft Excel software to calculate the probable time for the project. The results show that the project will be complete within 49.5 days, which is approximately 50 days as revealed in Table 1 below.

Activity Immediate Predecessor Duration in Days Optimistic Most Probable Pessimistic Expected Time Project Schedule The study uses the Microsoft Excel to develop the project schedule and output is revealed below: The PERT distribution to complete the project is in Fig 1 as follows Fig 1: PERT Distribution to Complete the Project The stimulation to determine the expected time to complete the Swimming Pool project with 90% confidence is as follows: Activity Variance Variance A (6-3)/36 0,08 B (6-2)/36 0,11 C (7-5)/36 0,06 D (10-7) /36 0,08 E (6-2)/36 0,11 F (3-1)/36 0,06 G (10-5)/36 0,14 H (10-6)/36 0,11 i (5-3)/36 0,06 Total 0,81 The next is to find the Standard Deviation (SD), which is the square root of the variance as follows: Thus, Square root of 0.81 =0.90 days.

Thus, there is 90% confidence that the project will complete at expected time. 3. What is the estimated probability that the project can be completed in 25 or fewer days? The critical part of the project is A-C-F and expected time is 12.83. The variance is 0.20, and the standard deviation is 0.44. Thus, P (X 25) is 65%. Problem II Activity Optimistic Most Probable Pessimistic Expected Times Variance A 4.0 5.0 6.0 B 2.5 3.0 3.5 C 6.0 7.0 8.0 D 5.0 5.5 9.0 E 5.0 7.0 9.0 F 2.0 3.0 4.0 G 8.0 10.0 12.0 H 6.0 7.0 14.0 Optimistic Most Probable Pessimistic Expected Time Variance a m b A 4 5 6 5,00 0,06 B 2,5 3 3 2,92 0,01 C 6 7 8 7,00 0,06 D 5 5,5 9 6,00 0,11 E 5 7 9 7,00 0,11 F 2 3 4 3,00 0,06 G 8 10 12 10,00 0,11 H.