Researchers hypothesize that people take longer to leave a parking spot when someone's waiting. They watched shoppers as they left a mall. They watched the parking spaces closest to the mall entrance, and timed the shoppers from when they opened their car door to when they had completely left the parking space. They also noted what group the shoppers were in those that had another car waiting for their spot, and those that did not have another car waiting. For 200 drivers observed, the time to leave the parking space were If another car waiting for spot average of 39.03 seconds (standard deviation 12.21 seconds) If no other cars waiting for spot....... average of 32.15 seconds (standard deviation 5.13 seconds) Is this a controlled experiment or an observational study? How do you know? What is the independent (experimental) variable? What is the dependent (responding) variable? What is the control group? What are the controlled variables?