A company wants to study the effectiveness of a new pain relief medicine. They recruit 100 volunteers with chronic pain.
Each subject takes the new pain relief medicine for a 2-week period, and a placebo for another 2-week
period. Subjects don't know which pill is the actual medicine, and the order of the pills is randomly assigned
for each subject. Researchers will measure the difference in the overall pain level for each s&oject.
What type of experiment design is this?