and possible vasectomy. For comparison, the same interview was given
to a sample of men selected from the population of these counties by
dialing telephone numbers at random. The data, tabulated by religious
background, are given in Table E4.14. Calculate the 95% confidence
interval for the odds ratio associated with vasectomy for each religious
group. Is there any evidence of an e¤ect modification?TABLE E4.14
Religion Vasectomy Cases Controls
Protestant Yes 24 56
No 205 239
Catholic Yes 10 6
No 32 90
Others Yes 18 39
No 56 964.15 A case–control study was conducted relating to the epidemiology of
breast cancer and the possible involvement of dietary fats, along with
vitamins and other nutrients. It included 2024 breast cancer cases who
were admitted to Roswell Park Memorial Institute, Erie County, New
York, from 1958 to 1965. A control group of 1463 was chosen from
patients having no neoplasms and no pathology of gastrointestinal or
reproductive systems. The primary factors being investigated were vita-
mins A and E (measured in international units per month). The data
listed in Table E4.15 are for 1500 women over 54 years of age.
TABLE E4.15
Vitamin A (IU/month) Cases Controls
a150,500 893 392
>150,500 132 83
Total 1025 475(a)Calculate the 95% confidence interval for the proportion among the
controls who consumed at least 150,500 international units of vita-
min A per month.
(b)Calculate the 95% confidence interval for the odds ratio associated
with vitamin A deficiency.4.16 A study was undertaken to investigate the e¤ect of bloodborne environ-
mental exposures on ovarian cancer from an assessment of consumption
of co¤ee, tobacco, and alcohol. Study subjects consist of 188 women in
the San Francisco Bay area with epithelial ovarian cancers diagnosed in
178 ESTIMATION OF PARAMETERS