12150
122203
21170
21242
221217
222220
31114
3123
32196
32250;
PROC FREQ;
WEIGHT COUNT;
TABLES SMOKESHIPCANCER/CMH;
The result is given in a chi-square form (X^2 ¼ 7 :601,p¼ 0 :006); CMH stands
for the Cochran–Mantel–Haenszel statistic; noting thatð 2 : 76 Þ^2 ¼ 7 :601.
Example 6.9 A case–control study was conducted to investigate the relation-
ship between myocardial infarction (MI) and oral contraceptive use (OC). The
data, stratified by cigarette smoking, are given in Table 6.11. An application of
the Mantel–Haenszel procedure yields the results shown in Table 6.12. The
combinedzscore is
TABLE 6.12
Smoking
No Yes
a 425
r 1 c 1
n
2.52 18.70
r 1 r 2 c 1 c 2
n^2 ðn 1 Þ
2.25 14.00
ad
n3.57 18.84
bc
n
2.09 12.54TABLE 6.11
Smoking OC Use Cases Controls
No Yes 4 52
No 34 754
Yes Yes 25 83
No 171 853
222 COMPARISON OF POPULATION PROPORTIONS