Do homes with metal roofs get worse cell service than homes with shingled roofs? Ben and Jerry are neighbors and own an ice cream business together. Ben has a metal roof on his home and Jerry has a shingled roof. Ben and Jerry select a random sample of 50 employees. They randomly assign them to come to a party at either Ben’s house or Jerry’s house. When they arrive Ben and Jerry ask them about their signal strength. Was this an observational study or an experiment? Justify your answer.