A drug researcher decides to test a new arthritis pain medication for safety and effectiveness on a treatment group of 100 severely disabled arthritis sufferers in a hospital ward. Everyone in the group is assigned a number. Patients with an even number receive the drug. Patients with an odd number receive a placebo.

Which of the following principles of experimental design are being followed?

Check all that apply.

A. Replication
B. Blindness
C. Blocking
D. Randomization
E. Lurking