If daily water demand is approximately normally distributed with a mean of 5 ml and a standard deviation of 1.25ml:
Estimate the number of days in a (365 day) year on which daily consumption is:
50% or more greater than the mean?
within two standard deviation of the mean?
below the first quartile level of demand?
If the water supply authority decides to save money by setting supply capacity to a level adequate to satisfy daily demand on 95% of all days at what level should capacity be set?