This document discusses audit sampling techniques for tests of controls and substantive tests of transactions. It defines key sampling concepts such as representative samples, sampling risk, nonsampling risk, statistical versus nonstatistical sampling, and probabilistic versus nonprobabilistic sample selection. The document provides details on specific sample selection methods and guidelines for determining tolerable exception rates, acceptable risk of assessing control risk too low, and expected population error rates when planning a sample. It also outlines the steps for selecting a sample, performing tests, and evaluating results to generalize to the population. The most commonly used statistical sampling method for these audit tests is attributes sampling which is based on the binomial distribution.