Past exam of the mathematics course of the University of Cambridge 2022 iii Paper 219 1 c Solution 2026-09-28
Letand setThe within-galaxy contrasts contain no , so the parameter-dependent log-likelihood reduces toThe score equations give the maximum-likelihood estimatorsThe calibrator and Hubble-flow samples are independent, so both estimators are unbiased andThe Fisher information matrix for isHence : attains the multiparameter Cramer-Rao bound.
Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 207 2 c i Solution 2026-09-28
For each substudy define the log-odds treatment effectThe normal random-effects log-likelihood, up to an additive constant, isIts score equations giveThese are the maximum-likelihood estimators rather than the unbiased sample-variance estimator. At an interior solution with , the Hessian in is negative definite, which is the required second-order condition.
Past exam of the mathematics course of the University of Cambridge 2023 iii Paper 207 6 b v Solution 2026-09-28
Ignoring factors that do not depend on , each observed side-effect contributes and each censored observation contributes . ThusThe score equation givesThis event-count divided by person-time estimator is the sample analogue of the expectation ratio in part iv.