after drinking. Data were tabulated separately for men and women
(Table E1.8).TABLE E1.8
Myocardial
Infarction Coronary Death
Drink in the
Last 24 Hours Controls Cases Controls Cases
Men No 197 142 135 103
Yes 201 136 159 69
Women No 144 41 89 12
Yes 122 19 76 4(a) Refer to the myocardial infarction data. Calculate separately for
men and women the odds ratio associated with drinking.
(b)Compare the two odds ratios in part (a). When the di¤erence is
confirmed properly, we have an e¤ect modification.
(c) Refer to coronary deaths. Calculte separately for men and women
the odds ratio associated with drinking.
(d) Compare the two odds ratios in part (c). When the di¤erence is
confirmed properly, we have an e¤ect modification.1.9 Data taken from a study to investigate the e¤ects of smoking on cervical
cancer are stratified by the number of sexual partners (Table E1.9).
TABLE E1.9
Cancer
Number of Partners Smoking Yes No
Zero or one Yes 12 21
No 25 118
Two or more Yes 96 142
No 92 150(a) Calculate the odds ratio associated with smoking separately for the
two groups, those with zero or one partner and those with two or
more partners.
(b)Compare the two odds ratios in part (a). When the di¤erence is
confirmed properly, we have an e¤ect modification.
(c) Assuming that the odds ratios for the two groups, those with zero or
one partner and those with two or more partners, are equal (in other
words, the number of partners is not an e¤ect modifier), calculate the
Mantel–Haenszel estimate of this common odds ratio.EXERCISES 37