A drug manufacturer believes it has developed a faster-acting pain-relief medication. To test the new drug, researchers identify 45 subjects who suffer from frequent headaches. The subjects are randomly assigned to take one of three treatments when they experience their next headache: the new medication, a currently available medication, or a sugar pill. All pills are manufactured to look identical to each other. The subjects will record the amount of time it takes to experience pain relief.
Which of the following statements is true?
I. Some subjects might perceive quicker pain relief simply because they've taken a pill (either active medication or sugar pill). Researchers control this placebo effect by giving all subjects a pill.
II. The sugar pills are a part of the blinding in this experiment.
III. The researchers use the sugar pills in order to determine the effects of sugar on pain relief.