A study took a random sample of students and asked them how many hours they studied and how many hours they played video games on the day before a test. The data showed that students who spent more time studying earned higher test scores than than students who spent more time playing video games.

Is the study observational or experimental? If it is an experiment, what is the controlled factor?

Select the correct answer below:

The study is an observational study.

The study is an experiment. The controlled factor is student's test scores.

The study is an experiment. The controlled factor is the survey.

The study is an experiment. The controlled factor is time spent playing video games.