A <group sequential design> can stop early for efficacy or futility, reducing expected sample size, cost, and time and limiting exposure to an inferior treatment. Its disadvantages include greater design and operational complexity, a potentially larger maximum sample size, and the need for adjusted stopping boundaries and inference to preserve the type I error after repeated looks.

Solution

Past exam of the mathematics course of the University of Cambridge / 2021 / iii / Paper 207 / 3 / b / i / Solution

 Solution (source code)