A medical doctor believes that the presence of aromatherapy will reduce the anxiety of first-time mothers-to-be during labor/delivery, and will increase their reported satisfaction with their care at his hospital. He randomly assigns mothers to give birth in a room environment either with or without aromatherapy. What is the independent variable in this example?

These are the options :

A. Anxiety level during labor

B. Number of previous birthing experiences

C. Presence or absence of aromatherapy

D. Satisfaction with hospital care

The answer is C. The presence or absence of aromatherapy

The independent variable is the room environment which is being controlled in the experiment . The room environment has to do with the presence or absence of aromatherapy for the mothers in labor.