Problem 5 In 2008, New York City implemented a law that required chain restaurants to post the calorie content of food items on their menus. The goal of this law was to combat obesity by providing information that, it was hoped, would induce people to consume fewer calories. You are asked to evaluate the impact of this law and decide to perform a study comparing New York to a control city. a) Why do you need a control city? b) What characteristics would you look for in a control city? c) Suppose that you have chosen Philadelphia as your control city and collect the following information on daily calorie consumption: Philadel-hia 2005 2556 2660 2007 2528 2625 2009 2461 2601 (1) Does the data before policy implementation suggest that Philadelphia is a good control for New York? Why? e) Compute a difference-in-difference estimate of the impact of the calorie posting policy. Interpret your estimate as a policy impact