How is random sampling used in stratified sampling?

In stratified sampling, random sampling is applied to ensure that each subgroup, or stratum, within the population is represented in the sample. This method involves identifying specific characteristics that define different strata (such as age, gender, income level, etc.), and then randomly selecting participants from each of these groups.

The process of assigning numbers to individuals in a stratum and randomly selecting from those numbers—akin to drawing names from a hat—ensures that every individual within that stratum has an equal chance of being selected. This randomness within each stratum helps mitigate sampling bias and allows for more accurate estimates of the entire population by ensuring that particular subgroups are adequately represented in the final sample. Stratified sampling benefits from the strengths of random sampling to achieve a more comprehensive understanding of the population's characteristics.

The other options do not accurately reflect the correct application of random sampling within stratified sampling. Calculating averages does not involve the selection of participants, which is a core aspect of stratified sampling. Selecting strata after identifying groups misrepresents the foundational step of stratifying the population before sampling. Lastly, only sampling from the largest stratum ignores the fundamental principle of stratified sampling, which aims to give all strata representation, rather than over-re