Final answer:
Convenience sampling is the most commonly used sampling method in psychological research due to its practicality, though it may produce biased data.
Step-by-step explanation:
The most commonly used sampling method in psychological research is probably convenience sampling. Convenience sampling is a nonrandom method of selecting a sample; this method selects individuals that are easily accessible and may result in biased data. Because it is not practical to measure the entire population in a study, researchers utilize various sampling methods such as random sampling, which includes simple random sampling, stratified sampling, cluster sampling, and systematic sampling. Convenience sampling often produces biased data, but it is commonly used due to its ease and practicality.