Across the country, the price of a gallon of milk from market to market is fairly constant. The same goes for cars and most other consumer products. But what about medical procedures? A team out of the University of Iowa called 120 hospitals across the country to compare the cost of a hip replacement paid out of pocket — and found wild variation in price. Robert Siegel talks with two members of the research team, Peter Cram and Jamie Rosenthal, about their findings.