In the article Randomised clinical trial: yoga vs written self-care advice for ulcerative colitis. (Aliment Pharmacol Ther., April 2017), 77 patients with ulcerative colitis were randomly assigned to yoga or written self-care advice.
"The yoga group had significantly higher disease-specific quality of life compared to the self-care group after 12 weeks."
Which best describes the type of study?
a. An observational study comparing two populations
b. An experiment comparing two treatments