Documentation for INFERT.DAT  (free format)

#  VARIABLE                CODES
-  -------------           ------------------------------

1  Education               0 = 0-5  year
                           1 = 6-11 years
                           2 = 12+  years

2  age                     age in years of case

3  parity                  count

4  number of prior         0 = 0    
   induced abortions       1 = 1  
                           2 = 2 or more

5  case status             1 = case 
                           0 = control

6  number of prior         0 = 0 
   spontaneous abortions   1 = 1   
                           2 = 2 or more

7  matched set number      1-83

8  group 2 indicator       1 = var4 is 1 / var6 is 0
                           0 = otherwise

9  group 3 indicator       1 = var4 is 2 / var 6 is 0
                           0 = otherswise

10 group 4 indicator       1 = var4 is 0 / var 6 is 1
                           0 = otherwise

11 group 5 indicator       1 = var4 is 1 / var 6 is 1
                           0 = otherwise

12 group 6 indicator       1 = var4 is 2 / var6 is 1
                           0 = otherwise

13 group 7 indicator       1 = var4 is 0 / var 6 is 2
                           0 = otherwise

14 group 8 indicator       1 = var4 is 1 / var 6 is 2
                           0 = otherwise

15 stratum number          1-63 (matched sets with same 
values
                                of the matching variables  
pooled)

-------------------------

Data are taken from Trichopoulos et al. (1976)
Br. J. of Obst. and Gynaec.vol.83, pp. 645-650.
There are 248 records. One case with two prior
spontaneous abortions and two prior induced
abortions is omitted.