59 epileptics were randomly assigned to either an anti-seizure medication (Progabide,
n=31) or placebo (n=28). The number of seizures experienced by each was recorded for 8 
weeks (before the drugs were given) and then for four consecutive 2 week periods. We  
also know the age of each participant.

These data were used in Thall and Vail (1990), Breslow and Clayton (1993), and 
Diggle, Liang, and Zeger (1994).