A lab technician is studying the time it takes for a a pharmaceutical drug to take effect in a sample of 120 study participants. The technician divides the sample in three groups according to how the drug will be taken - the first group takes the drug 30 minutes before eating, the second group takes the drug along with food, and the third group takes the drug 30 minutes after eating. Which of the following is true?
Select the correct answer below:
The research is an observational study
The study is an experiment. The controlled factor are the number of participants in the test.
This is neither an observational study nor an experiment.
The study is an experiment. The controlled factor is the time when the drug is taken relative to consuming food.