What type of sampling method ensures every individual has an equal chance of being selected?

The method that guarantees every individual in a population has an equal chance of being selected is random sampling. This technique involves selecting participants in such a way that each member of the population has a defined and non-zero probability of being chosen, ensuring fairness and minimizing bias in the selection process. This is crucial for ensuring that the sample is representative of the overall population, which can enhance the validity and reliability of research findings.

In random sampling, various methods such as lottery systems, random number generators, or other forms of chance selection are employed to achieve this equal opportunity. This contrasts sharply with the other methods mentioned. For example, convenience sampling focuses on individuals who are easiest to reach, which may lead to biased results as it does not account for the entire population. Systematic sampling involves selecting individuals based on a fixed interval, which can inadvertently introduce bias if there is an underlying pattern in the population related to that interval. Purposive sampling, on the other hand, selects individuals based on specific characteristics or purposes set by the researcher, which further reduces the likelihood of every individual having an equal chance of selection. Thus, random sampling stands out as the method that promotes equality and randomness in participant selection.