This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Principles of Epidemiology, Subject name: Social & Preventive Medicine
Kaplan Meier method is used for: 
Select and explain. 
A. Prevalance, B. Survival, C. Frequency, D. Incidence
B: Survival
Answer: B: Survival 
Explanation: Ans. is 'b' i.e. Survival The Kaplan-Meier estimator (also known as the product limit estimator) estimates the survival function from lifetime data. In medical research, it is used to measure the fraction of patients living for a certain amount of time after treatment.