Stratified Sampling

Also known as: Stratified Sample, Proportional Stratified Sampling

Probabilistic technique dividing the population into homogeneous strata and randomly selecting within each stratum.

Stratified Sampling is a probability sampling technique that divides the target population into mutually exclusive and exhaustive subgroups (strata) based on relevant variables (age, region, SES, etc.) and then randomly selects a sample within each stratum.

Its advantages over simple random sampling: (1) guarantees representation of all subgroups of interest, including minorities that might not appear in a simple random sample; (2) can improve statistical efficiency by reducing variance within each stratum; (3) allows separate analyses by subgroup with controlled precision.

It is the preferred method when comparing results across specific subgroups is required (e.g., analyzing differences between high-income and mid-income consumers).