1) A 10-year long study has enrolled 1500 men and women who work for the New York MTA to study the
association between prolonged exposure to noisy environments and the onset of hearing-loss. 2000 MTA
administrative office workers were also enrolled as controls. Participants were chosen based on how many
hours they are exposed to noisy environments (75 decibels or higher) and then followed in time to see if
they develop hearing loss of any magnitude. After 10 years, they found that 47 of the office workers had
developed hearing loss, and 158 of the workers in the noisy environment developed hearing loss.
i) Based on the information given above, what type of study design was used?
2) What is the best measure of association used for this study design type?
3) Use the information above to complete a 2×2 contingency table with proper labels for disease status,
exposure status and totals. Fill in all numbers (see lectures and textbook for examples)
4) Calculate the measure of association you indicated in question 2, showing all the steps.
5) Imagine you had to share the findings of this research with the workers, how would you explain your
answer in part 4 so that it makes sense to them? (Use your lectures or textbook for examples)
6) If you had to choose a different study design, other than the one described here, which would you
choose? Briefly explain what your study design would entail.