The correct answer is True
Step-by-step explanation:
Experimental studies or experiments involve the manipulation of one or more factors to prove a hypothesis or answer the main question of the study. This means in experiments, researchers intervene rather than only observe.
This occurs in the study presented because to discover the effect of an herbal treatment for depression the researchers give some participants the treatment and some only tea. This means there is an intervention in participants, and the researchers are manipulating one of the factors (number of participants that receive the treatment,) which are features of experiments.