The Department of Consumer Affairs is interested in the difference, D, between the price that people are quoted online for a domestic flight, and the price that they are actually charged. They seek online quotes for cost of a flight fares between twelve pairs of random locations, and then take these flights and record the actual price charged. They subtract the quoted price from the charged price. The results (in $), and their accumulations appear below. 55.10, 120.45, -26.0, 85.60, 130.80, -120, 77.30, 100.10, 15.10, 30.15, 99.95, 170.35 D = 748.90, D2 = 115,299.7, n = 12