9. The questions that follow are based on the data below: Age Population Population Incidence Standard A B rates/1000 in rates/1000 A and B 45-54 2000 400 10.0 5.0 55-64 800 600 15.0 7.0 65-74 400 2500 25.0 20.0 Total population 3200 3500 12/1000 Total number of cases Standardized Incidence ratio
Expected number of incident cases Population A Population B
a. Calculate age-standardized incidence rate ratios in populations A and B. For these calculations, an external study population should be used as the source of the standard rates. Note that the age-specific incidence rates are exactly. the.same in these two study populations. b. What is the interpretation of the standardized incidence (or mortality) ratio? c. Why. in spite of having the same age-specific incidence rates, was there such a fairly large difference in the standardized incidence ratio between populations A and B?