Based on observing more than 400 drivers in the Atlanta area, two investigators at Georgia State University concluded that people exiting parking spaces did so more slowly when a driver in another car was waiting for the space than when no one was waiting ("Territorial Defense in Parking Lots: Retaliation Against Waiting Drivers," Journal of Applied Social Psychology [1997]: 821-834). Describe how you might design an experiment to deter- mine whether this phenomenon is true for your city. What is the response variable? What are some extraneous variables and how does your design control for them?