Much discussion has taken place concerning possible health hazards from exposure to anesthetic gases. In one study 525 Michigan nurse anesthetists were surveyed by mail questionnaires and telephone interviews in 1972 to determine the incidence rate of cancer [9]. Of this group, 7 women reported having a new malignancy other than skin cancer during 1971.
1) What is the best estimate of the 1971 incidence rate from these data?
2) Provide a 95 percent CI for the true incidence rate.
A comparison was made between the Michigan report and the 1969 cancer-incidence rates from the Connecticut tumor registry, where the expected incidence rate, based on the age distribution of the Michigan nurses, was determined to be 402.8 per 100,000 person-years.
3) Comment on the comparison between the observed incidence rate and the Connecticut tumor-registry data.