1. Read Eye on Retailers' Costs on p. 365 and draw a graph to show how the retailers' cost curves would change if they introduced cost-saving self-checkouts.
2. If the ATC curves of a Wal-Mart store and a 7-Eleven store are like those in Eye on Retailers' Costs on p. 365, and if each type of store operates at its minimum ATC, which store has the lower total cost? How can you be sure? Which has the lower marginal cost? How can you be sure? Sketch each firm's marginal cost curve.