<prompt> All are true of attack rate except -It is type of prevalence rateExpressed as percentageUsed when population is exposed to risk for a limited period of timeReflects extent of epidemic  <response>: Ans. is a i.e., It is a type of prevalence rate Attack rate is a type of incidence rate Attack rate It is an incidence rate. It is also known as cumulative incident rate. Usually expressed as a percentage. o Used only when the population is exposed to risk for a limited period of time such as during an epidemic. 