Statistical sampling is known as a technique for selecting a sample from a population. When choosing a sample it is expected to make their properties extrapolated to the population. This process saves resources and time to obtain results similar to those that would be achieved when conducting a study of the entire population. It is worth mentioning that the sample should be valid and can make a proper study and must meet certain requirements. We can never be entirely sure that the result is a representative sample but, we can act so that this condition is achieved with a high probability. In sampling, if the sample size is smaller than the size of the city, we can extract two or more samples of the same population. The set of samples that can be obtained from the population is called the sample space. The variable associated with the probability of each sample extraction is called sampling distribution (Allen, Qian, Qian, 2007).