determined (Table E6.2). Use McNemar’s chi-square test to investigate
the significance of the association between estrogen use and endometrial
carcinoma; state your null and alternative hypotheses.TABLE E6.2
Controls
Cases Estrogen No Estrogen
Estrogen 39 113
No estrogen 15 1506.3 A study in Maryland identified 4032 white persons, enumerated in a
nono‰cial 1963 census, who became widowed between 1963 and 1974.
These people were matched, one to one, to married persons on the basis
of race, gender, year of birth, and geography of residence. The matched
pairs were followed in a second census in 1975, and the data for men
have been analyzed so as to compare the mortality of widowed men
versus married men (see Example 6.3). The data for 2828 matched pairs
of women are shown in Table E6.3. Test to compare the mortality of
widowed women versus married women; state your null and alternative
hypotheses.
TABLE E6.3
Married Women
Widowed
Women Dead Alive
Dead 1 264
Alive 249 23146.4 It has been noted that metal workers have an increased risk for cancer of
the internal nose and paranasal sinuses, perhaps as a result of exposure
to cutting oils. Therefore, a study was conducted to see whether this
particular exposure also increases the risk for squamous cell carcinoma
of the scrotum (see Example 6.2). Cases included all 45 squamous cell
carcinomas of the scrotum diagnosed in Connecticut residents from 1955
to 1973, as obtained from the Connecticut Tumor Registry. Matched
controls were selected for each case based on the age at death (within
eight years), year of death (within three years), and number of jobs as
obtained from combined death certificate and directory sources. An
occupational indicator of metal worker (yes/no) was evaluated as the
possible risk factor in this study. The results are shown in Table 6.2. Test
to compare the cases versus the controls using the McNemar’s chi square
test; state clearly your null and alternative hypotheses and choice of test
size.
EXERCISES 235