<prompt> Cross sectional study is associated with:Indicates prevalenceIncidencePositive predictive valueRelative risk  <response>: Ans. a Indicates prevalenceRef : K. Park 23rd ed. 75-77Cross sectional study is the simplest form of observational epidemiological study which is based on single examination of a cross section of a population at one point of time, results of sample are then projected to the whole populationAdvantages Provides prevalence of a disease Provides a whole picture of population at one point of time More useful for chronic diseaseDisadvantages Tells about distribution of a disease rather than the etiology Establishment of time sequence of a disease is not possible Provides little information of a natural history and incidence of a disease 