In a study in the UK, an association was found between the sale of antiarrhythmic drug and an increase in deaths due to asthma. This is an example of: (A) Ecological study, (B) Cohort study, (C) Case reference study, (D) Experimental study
Answer is A. Ans. is 'a' i.e. Ecological study Repeat May 08 www. ucel ac. uk. rlos/specs/rlo_observational_study. doc; http.//cancersupportivecare. com/epidemiology.html] For explanation see May 08