Answer Happy

According to a study published in the journal Psychological Medicine, ayahuasca - a drink made of Amazonian plants-can help people with depression. The study involved 29 participants who all had depression. Doctors gave each of the participants either ayahuasca or a placebo beverage that looked and tasted similar. Those who drank ayahuasca showed significantly lower levels of depression compared to those who drank the placebo beverage. What type of study is this, and what is the response variable? An observational study where depression level is the response variable An observational study where the type of drink is the response variable O A controlled experiment where depression level is the response variable A controlled experiment where the type of drink is the response variable