Past exam of the mathematics course of the University of Cambridge 2022 iii Paper 219 3 b Solution 2026-09-28
Let and . With the stated improper hyperpriors, the unnormalized posterior density isIts Directed acyclic graph has, for each star, the arrowsfollowed by the deterministic observation arrowsThe latent variables are repeated inside a plate indexed by ; all hyperparameters lie outside that plate.
Past exam of the mathematics course of the University of Cambridge 2025 ii Paper 4 28L c Solution Created 2026-09-24 Updated 2026-09-25
Sincethe first full conditional isHolding fixed and comparing powers and exponential rates givesThe assumed parity of makes a positive integer.
Initialize arbitrarily. At iteration , putDraw independent uniform variables and setBy sampling an integer-shape gamma distribution, this has the required law. Next draw independently and setThese are exactly the two full-conditional updates of the normal mean-precision Gibbs sampler. After discarding burn-in, the pairs are approximate samples from the posterior by Markov chain Monte Carlo.