data from Exercise 7.14, p225
twins data frame has 24 rows and 3 columns.
This data frame contains the following columns:
Age of twin's death from CHD, months
Death (male twin) from CHD indicator (1=dead from CHD, 0=alive or other
cause of death)
Klein and Moeschberger (1997) Survival Analysis Techniques for Censored
and truncated data, Springer.
Dataset imported from https://www.r-project.org.