STATS Problem 1 Exercise 6

1.
A study was conducted to evaluate the
association between benzene exposure and leukemia. Employment records
identified 10,000 workers who were occupationally exposed to benzene in the
1980s and 14,000 workers who were not occupationally exposed to benzene. These
records were subsequently linked with cancer registries to identify cases of
leukemia from 1990 to 2000. During this time there were 250 cases of leukemia
among the benzene-exposed workers and 120 cases among the unexposed workers.
a.
What kind of a study is this?
b.
Fill in the table.

Leukemia

No leukemia

Total

Benzene

No benzene

Total

c.
What is the risk of leukemia among workers who
were exposed to benzene?
d.
What is the risk of leukemia among workers who
were not exposed to benzene?
e.
Calculate the risk ratio
f.
Calculate the 95% confidence interval for the
risk ratio.
g.
Interpret the finding in one sentence.
h.
Calculate and interpret the risk difference and
its 95% confidence interval in the above sample.