8. Our Project – A Refresher Set up in visual form it might look like this… Set up in tabular form, it might look like this… ? Install Edging 8 ? Buy Edging 7 ? Plant Flowers 6 ? Plant Trees 5 ? Buy Flowers 4 ? Buy Trees 3 ? Dig Holes 2 ? Mark Utilities 1 Duration (Days) Description TASK ID
9. PERT Step 3 – First Get Organized In considering all tasks on the previous slide, a table might look like this T O -Optimistic T M -Likely T P -Pessimistic T E -Expected (Derived by PERT) Remember – tasks 3, 4 and 7 are concurrent and do not add to the timeline TOTAL 7 4 3 T E T P T L T O TASK OTHER PROJECT TASKS TOTAL 8 6 5 2 1 T E T P T L T O TASK CRITICAL PATH TASKS (Longest Duration)
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11. PERT Step 4 – Dates ES=Earliest Start EF= Earliest Finish LS=Latest Start LF=Latest Finish For each task, determine the latest allowable time for moving to the next task The difference between latest time and expected time is called slack time Tasks with zero slack time are on the critical path .51 1.26 3.75 9 3 1.5 TOTAL .17 .42 3 5.50 4.25 2.50 1.25 1.25 3 1 .5 7 .17 .42 3 4.25 3 1.25 0 1.25 3 1 .5 4 .17 .42 3 4.25 3 1.25 0 1.25 3 1 .5 3 V SD FLOAT LF LS EF ES T E T P T L T O TASK OTHER PROJECT TASKS 2.530 3.5 15.51 28 15 7 TOTAL .254 .5 0 15.17 13 15.17 13 2.17 4 2 1 8 .444 .67 0 13 10 13 10 3 5 3 1 6 .694 .83 0 10.17 7 10.17 7 3.17 6 3 1 5 .694 .83 0 7.17 3 7.17 3 4.17 7 4 2 2 .444 .67 0 3 0 3 0 3 5 3 1 1 V SD Slack LF LS EF ES T E T P T L T O TASK CRITICAL PATH TASKS (Longest Duration)
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14. PERT Step 5 – Probabilities Computing probability in Excel using data compiled in your table