Selection bias refers to the systematic error that occurs when the sample used in a study or experiment is not representative of the entire population, leading to inaccurate or biased results. This bias can occur when certain individuals or groups are more likely to be included in the sample, skewing the data and potentially leading to incorrect conclusions. It can also arise when the selection process is influenced by factors such as personal bias, convenience, or self-selection. In order to minimize selection bias, researchers must carefully consider their sampling methods and strive for a diverse and unbiased sample that accurately reflects the population being studied.