of 793 people involved in bicycle accidents during a one-year period
(Table E6.14). Test to compare the proportions with head injury, those
with helmets versus those without; state clearly your null and alternative
hypotheses and choice of test size.TABLE E6.14
Wearing Helmet
Head Injury Yes No
Yes 17 218
No 130 428
Total 147 6466.15 A case–control study was conducted relating to the epidemiology of
breast cancer and the possible involvement of dietary fats, along with
other vitamins and nutrients. It included 2024 breast cancer cases
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 reproduc-
tive systems. The primary factors being investigated were vitamins A and
E (measured in international units per month). The data shown in Table
E6.15 are for 1500 women over 54 years of age. Test to compare the
proportions of subjects who consumed less vitamin A (a150,500 IU/
month), cases versus controls; state clearly your null and alternative
hypotheses and choice of test size.
TABLE E6.15
Vitamin A (IU/month) Cases Controls
a150,500 893 392
>150,500 132 83
Total 1025 4756.16 In a randomize trial, 111 pregnant women had elective induction of
labor between 39 and 40 weeks, and 117 controls were managed expec-
tantly until 41 weeks. The results are shown in Table E6.16. Use Fisher’s
exact test to verify the alternative that patients with elective induction
have less meconium staining in labor than do control patients.
TABLE E6.16
Induction Group Control Group
Number of patients 111 117
Number with meconium staining 1 13EXERCISES 239