In random sampling, subjects are selected based on which of the following criteria?

In random sampling, the key principle is that every member of the population being studied has an equal chance of being selected. This method helps ensure that the sample is representative of the larger population, which minimizes bias and allows for the generalizability of the findings. By giving every individual within the population the same likelihood of selection, researchers can make more robust statistical inferences about the population based on the sample data.

This approach contrasts with convenience sampling, which involves selecting subjects based on their availability or ease of access, and does not guarantee that every member of the population has an equal chance of being included. Options that suggest subjects do not know they will be chosen or are selected as they become available do not align with the principles of random sampling, as they imply a lack of systematic selection criteria that ensures representativeness. The focus on equal chance is what makes random sampling a powerful tool in research methodologies.