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.
Find the: a. mean of the population. b. standard deviation of the population. c. mean of the sampling distribution of the mean. d. standard error of the mean. Problem 11. The times required for workers to complete a certain task are normally distributed with a mean of 30 minutes and a standard deviation of 9 minutes.If a random sample of 25 workers is drawn from the work force, find the probability that the mean completion time for the sample of workers is between 28 and 33 minutes.he times required for workers to complete a certain task are normally distributed with a mean of 30 minutes and a standard deviation of 9 minutes. If a random sample of 25 workers is drawn from the work force, find the probability that the mean completion time for the sample of workers is between 28 and 33 minutes.