Replacement sampling is a statistical method where each item selected from a population is returned before the next selection. This means that the same item can be chosen more than once, allowing for a larger variety of possible samples. It is often used in scenarios where the population size is limited or when researchers want to maintain the same probability of selection for each item. This technique is commonly applied in fields like statistics, market research, and quality control. By using replacement sampling, researchers can ensure that their samples are representative of the overall population, which helps in making accurate inferences and decisions based on the collected data.