For example, if a scientist suspects caffeine intake affects behavioral changes in children, he may choose to conduct a(n) study where he randomly assigns children in the study to either a regular, normal-caffeine level diet or a high-caffeine diet group and then studies behavior without knowing which group received which diet.

Randomized, Double-Blind Placebo Controlled Study

Explanation:

It is a medicinal report including human members in which neither one of the sides knows what treatment is given to each and placebo treatment are given to a control gathering.  The specialists choose arbitrarily with respect to which members in the preliminary get the new treatment and which get a fake treatment, or phony treatment. In the control gathering, the members don't get the new treatment however rather get a fake treatment or reference treatment.

Answer charlie should immediately start an exercise and diet program because all his test indicate that he is extremely obese;