<prompt> 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 ofEcological studyCohort studyCase reference studyExperimental study  <response>: Ans. is a i.e. Ecological study Repeat May 08 www. ucel ac. uk. rlosspecsrlo_observational_study. doc; http.cancersupportivecare. comepidemiology.html For explanation see May 08 