Past exam of the mathematics course of the University of Cambridge 2009 iii Paper 36 2 a Solution Created 2026-10-03 Updated 2026-10-14
Under the discrete uniform distribution, the observation has probability when its value is an available label, and zero otherwise. Therefore the likelihood function isThis is the discrete uniform endpoint posterior model's likelihood; all endpoints smaller than the observed label are excluded.
Past exam of the mathematics course of the University of Cambridge 2009 iii Paper 36 2 f Solution Created 2026-10-03 Updated 2026-10-14
Multiplying the reciprocal improper prior by the likelihood function givesThus this discrete uniform endpoint posterior is proper. Its exact cumulative probability is . Integral approximation gives and , soThese approximations are useful when is moderately large and are not exact discrete identities. For example the exact untruncated median at is . Although its quantiles are finite, its posterior mean is infinite, since its expectation numerator is the divergent sum .