to study whether there is a correlation between regular exercise and sleep a researcher randomly selected 100 people who exercise regularly and 100 people who do not exercise regularly, and compared how many hours they sleep at night on average. is the study observational or experimental? if it is an experiment what is the controlled factor O the study is an experiment. The controlled factor is the amount of sleep O the study is an experiment. The controlled factor is the amount of exercise O the study is observational study. O the study is an experiment. The controlled factor is the survey