You are the epidemiology consultant to a cotton candy making factory. There is some suspicion about exposure at the factory and occurrence of respiratory disease among the workers. You conduct a study to collect data about exposure to cotton candy making and respiratory disease. The incidence of respiratory disease among workers exposed to cotton candy = 200 per 100,000 per year. The incidence of respiratory disease among workers not exposed to cotton candy = 20 per 100,000 per year. Incidence in the general population is 21 per 100,000 per year.

a) Assuming that you believe this relationship is causal, if an exposed worker develops respiratory disease, what is likelihood that the disease as a result of his/her employment?

b) What would account for the low PAR% in view of the high AR and high relative risk?

c) Assuming that you believe this relationship is causal, if an exposed worker develops respiratory disease, what is likelihood that the disease as a result of his/her employment?

d) In making recommendations to management concerning the desirability of extra protection for the workers, which measure of excess risk would be most informative? Why?

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