The water-treatment plant at an air station in California was constructed for a design capacity of 4,500,000 gal/day (domestic use). It is nearly always necessary to suspend lawn irrigation when demand exceeds supply. There are, of course, attendant losses. Measured demands during July and August 1965 (weekdays only) were (in thousands of gallons per day, ordered data):
Compute sample mean and variance. Construct a cumulative histogram in which 4,500,000 gal/day is one of the interval boundaries. On a relative frequency basis, how often did demand exceed capacity?