One of the most important things in auditing project of technology development is guarantee that the products of the project are agreeing with the specifications and the expectation of the owner. In some case is unpractical to examine all the component or documentation in the project. Then if that element for examine have some characteristic or properties, is possible to take a sample and make inferences about the work with a risk under control. In this document is combine the main elements for take a sample in statistic point of view, and a standard process of defined the size of the sample, the methodology of selection and the way of make inferences about the population from the sample.