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.
Total float represents the amount of time an activity can be delayed without delaying the overall project duration and is also called âfloatâ or âslackâ. Free Float. Free float is measured by subtracting the early finish (EF) of the activity from the early start (ES) of the successor activity. Free float represents the amount of time that a schedule activity can be delayed without delaying the early start date of any immediate successor activity within the network path. Free float is only calculated on the last activity in an activity sequence.