3.8 An advertising agency chooses an ESPN television ad.

An advertising agency developed two versions of an ad that will be shown during a major sporting event on EPSN but must choose only one to air. The agency recruited 100 college students and divided them into two groups of 50. Each group viewed one of the versions of the ad and then answered a collection of questions about their reactions to the ad. Is the advertising agency using an observational study or an experiment to help make its decision? Give reasons for your answer.