Editing Gantt chart (section)

== Example ==
{{unreferenced section|date=March 2024}}
In the following tables there are seven tasks, labeled ''a'' through ''g''. Some tasks can be done concurrently (''a'' and ''b'') while others cannot be done until their predecessor task is complete (''c'' and ''d'' cannot begin until ''a'' is complete). Additionally, each task has three time estimates: the optimistic time estimate (''O''), the most likely or normal time estimate (''M''), and the pessimistic time estimate (''P''). The expected time (''T<sub>E</sub>'') is estimated using the [[Beta distribution#Project management: task cost and schedule modeling|beta probability distribution]] for the time estimates, using the formula (''O''&nbsp;+&nbsp;4''M''&nbsp;+&nbsp;''P'')&nbsp;÷&nbsp;6.

{| class="wikitable" style="text-align:right"
|-
!rowspan="2" | Activity
!rowspan="2" | Predecessor
!colspan="3" | Time estimates (in days)
!rowspan="2" | Expected time (''T<sub>E</sub>'')
|-
! Opt. (''O'')
! Normal (''M'')
! Pess. (''P'')
|-
! ''a''
| {{sdash}}
| 2
| 4
| 6
| 4.00
|-
! ''b''
| {{sdash}}
| 3
| 5
| 9
| 5.33
|-
! ''c''
| style="text-align:center" | ''a''
| 4
| 5
| 7
| 5.17
|-
! ''d''
| style="text-align:center" | ''a''
| 4
| 6
| 10
| 6.33
|-
! ''e''
| style="text-align:center" | ''b'', ''c''
| 4
| 5
| 7
| 5.17
|-
! ''f''
| style="text-align:center" | ''d''
| 3
| 4
| 8
| 4.50
|-
! ''g''
| style="text-align:center" | ''e''
| 3
| 5
| 8
| 5.17
|}

Once this step is complete, one can draw a Gantt chart or a network diagram.

[[File:pert example gantt chart.gif|frame|none|A Gantt chart created using [[Microsoft Project]]. Note (1) the [[critical path method|critical path]] is in red, (2) the [[Float (project management)|slack]] is the black lines connected to non-critical activities, (3) since Saturday and Sunday are not work days and are excluded from the schedule, some bars on the Gantt chart are longer if they cut through a weekend.]]