1 For example, the disorder sickle cell anaemia is caused by a mutation in the gene that instructs the building of a protein called haemoglobin. 2  This causes the red blood cells to become an abnormal, rigid, sickle shape. 3  However, in African populations, having this mutation also protects against malaria.
Optimistic time - generally the shortest time in which the activity can be completed. It is common practice to specify optimistic times to be three standard deviations from the mean so that there is approximately a 1% chance that the activity will be completed within the optimistic time.
To determine the project activity durations, the PM must consider the amount of effort required and the project resources that are available and will be used. Effort is the number of work units. Duration is the total time required based on the effort and the resources available (minus holidays and non-work days). Elapsed time is the calendar time (includes all dates, such as holidays and non-work days). See all posts in our PMP Concepts Learning Series.