including 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 in Table E1.40 are tabulated by
religious background. Calculate the odds ratio associated with vasec-
tomy for each religious group. Is there any evidence of an e¤ect modifi-
cation? If not, calculate the Mantel–Haenszel estimate of the common
odds ratio.1.41 The role of menstrual and reproductive factors in the epidemiology of
breast cancer has been reassessed using pooled data from three large
case–control studies of breast cancer from several Italian regions. The
data are summarized in Table E1.24 for age at menopause and age at first
live birth. Find a way (or ways) to summarize the data further so as to
express the observation that the risk of breast cancer is lower for women
with younger ages at first live birth and younger ages at menopause.
1.42 In 1979 the U.S. Veterans Administration conducted a health survey of
11,230 veterans. The advantages of this survey are that it includes a large
TABLE E1.42
Service in Vietnam
Symptom Yes No
Nightmares
Yes 197 85
No 577 925
Sleep problems
Yes 173 160
No 599 851
Troubled memories
Yes 220 105
No 549 906
Depression
Yes 306 315
No 465 699
Temper control problems
Yes 176 144
No 595 868
Life goal association
Yes 231 225
No 539 786
Omit feelings
Yes 188 191
No 583 821
Confusion
Yes 163 148
No 607 864EXERCISES 53