This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Experimental studies are meant to - 
Select and explain. 
A. Test etiological hypothesis, B. Find out prevalence rates, C. Find out cause of epidemics, D. To find out the history of disease
A: Test etiological hypothesis
Answer: A: Test etiological hypothesis 
Explanation: Experimental studies involve an active attempt to change a disease determinant or the progress of a disease and are similar in design to experiments in other sciences. The major experimental design is randomized control trials. Field trials and community trials are other experimental studies. (refer pgno:63 park 23 rd edition)