<prompt> About direct standardization all are true except ?Age specific death rate is not neededA standard population is neededPopulation should be comparableTwo populations are compared  <response>: Ans. is a i.e., Age specific death rate is not needed Direct standardization Direct standardization is used when the study population is large enough that age specific rates within the population are stable. o Direct standardization is commonly used in repos of vital stastics e.g., moality or disease incidence trend e.g. cancer incidence. o A standard population reference population is selected for which the numbers in each age and sex group are known. o Next, age-specific rates of study population population whose crude death rate is to be adjusted or standardized are computed. o Then, these age specific rates of study population are applied to standard population by multiplying these rates by the number of people in that age group in the study population. o These expected rates are summed and divided by the total population size of standard population to yield the directly standardized rates. 