This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiological Study, Subject name: Social & Preventive Medicine
[{'content': 'Incidence is calculated by- \nSelect and explain. \nA. Retrospective study, B. Prospective study, C. Cross sectional study, D. Random study', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Prospective study o Incidence rate is measured by cohort study, also known as prospective study.Epidemiological studyParameter obtainedo Case control studyOdds ratioo Cohort studyIncidence rateRelative riskAttributable riskPopulation attributable risko Cross - sectional studyPrevalenceo Ecological studyGroup characteristics", 'role': 'assistant'}]