This course applies basic concepts of probability and statistics to systems consisting of a large number of particles to determine measurable macroscopic quantities such as temperature, pressure, energy, and heat capacity. Emphasis is placed on the calculation of the canonical and grand canonical partition functions for various model physical systems. Particular attention is focused on three ideal gas systems: a gas consisting of massive Maxwell-Boltzmann particles, a gas consisting of massless bosons (i.e., photons), and a gas consisting of fermions.