epidemiologists measure disease frequency, they analyze the incidence and
prevalence of a disease. Incidence is the number of new cases of a disease in a
particular population during a specific time period. This measure is useful
when public health officials and epidemiologists are looking at the first
occurrence of a disease. It is also important when comparing populations to determine
disease risk.

For each problem,
answer the following questions:

Name the appropriate
measure of disease frequency that should be used in each scenario and justify
its use (why that particular measure is the appropriate one).

1) The
percentage of elderly men who are diagnosed with prostate cancer by age 80.