Answer to Question 1
Ans: B
The concept of relative risk applies when one group of people clearly is exposed and another is not exposed to an external factor such as cigarette smoke, exercise, or foods high in saturated fat. However, it may be confusing to see relative risks applied to internal factors such as age, race, or gender.
Answer to Question 2
Ans: D
The majority of rates are based on data from a calendar year, which may also present some difficulties. Populations may increase or decrease during a calendar year. To adjust for population changes over the year, the midyear population estimate is generally used because the population at risk cannot be determined accurately.