Researchers wish to determine if a new experimental medication will reduce the symptoms of allergy sufferers without the side-effect of drowsiness. To investigate this question, the researchers give the new medication to 50 adult volunteers who suffer from allergies. Forty-four of these volunteers report a significant reduction in their allergy symptoms without any drowsiness.

(a) This study could be improved by

A. including people who do not suffer from allergies in the study in order to represent a more diverse population.
B. using a control group.
C. repeating the study with only the 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness, and giving them a higher dosage this time.
D. all of the above.

(b) This is an example of

A. a block design.
B. the establishing of a causal relationship.
C. a randomized study.
D. a double blind experiment.
E. None of the above.

(c) The experimental units are

A. the researchers.
B. the six volunteers who did not report a significant reduction in their allergy symptoms without any drowsiness.
C. the 44 volunteers who reported a significant reduction in their allergy symptoms without any drowsiness.
D. the 50 adult volunteers.