Past exam of the mathematics course of the University of Cambridge / 2022 / iii / Paper 207 / 4 / b

In a constant hazard survival model, the maximum-likelihood estimator is the number of observed events divided by total person-time at risk. Treatment A contributes $3$ deaths in $1+2+3+3+5=14$ months, while Treatment B contributes $2$ deaths in $1+5+5+7+10=28$ months. Hence