format
This data frame contains the following columns:
rl{
set: Case-control set: a numeric vector
d: Case or control: a numeric vector (1=case, 0=control)
gall: Gall bladder disease: a factor with levels
No
Yes.
hyp: Hypertension: a factor with levels
No
Yes.
ob: Obesity: a factor with levels
No
Yes.
est: A factor with levels
No
Yes.
dur: Duration of conjugated oestrogen therapy: an ordered factor with levels
0 < 1 < 2 < 3 < 4.
non: Use of non oestrogen drugs: a factor with levels
No
Yes.
duration: Months of oestrogen therapy: a numeric vector.
age: A numeric vector.
cest: Conjugated oestrogen dose: an ordered factor with levels
0 < 1 < 2 < 3.
agegrp: A factor with levels
55-59
60-64
65-69
70-74
75-79
80-84
age3: a factor with levels
<64< code="">
65-74
75+
}source
Breslow NE, and Day N, Statistical Methods in Cancer Research. Volume
I: The Analysis of Case-Control Studies. IARC Scientific
Publications, IARC:Lyon, 1980.