Data on 12 sets of male/female twins
See Problem 7.8.14
Data can be read in free format. The variables represented in the dataset are as follows: 

Twin number 
Age of male twin's death from CHD, months 
Death (male twin) from CHD indicator (1=dead from CHD, 0=alive or other cause of death) 
Age of female twin's death from CHD, months 
Death (female twin) from CHD indicator (1=dead from CHD, 0=alive or other cause of death) 
THE DATA 
1 50 1
1 63 0
2 49 0
2 52 1
3 56 0
3 70 0
4 68 1
4 75 1
5 74 0
5 72 1
6 69 0
6 69 0
7 70 0
7 70 0
8 67 1
8 70 0
9 74 0
9 74 0
10 81 0
10 81 0
11 61 1
11 58 1
12 75 0
12 73 0