A researcher wishes to examine the effects of a new medical treatment on
patients with Alzheimer's disease. The researcher plans to examine the
effects on a group of randomly selected subjects. What is wrong with this
design?
Select all that apply.
A. Subjects are not randomly assigned to an experimental group and
control group.
B. A control group is not used.
C. Only one researcher is used.
D. An entire population is not used.