What is Stratified Sampling?

Stratified sampling is a statistical method that involves dividing a population into smaller subgroups, or "strata," that share similar characteristics. The primary purpose of this approach is to ensure that each subgroup is adequately represented in the final sample. By sampling from each sublot, the technique increases the likelihood that the sample reflects the diversity of the overall population, thus leading to more reliable and valid results.

In the context of quality control and data analysis, this method is particularly useful when the characteristics of each stratum can vary significantly. For example, if a construction project has multiple layers of material with different properties, stratified sampling would involve taking samples from each of these layers, ensuring that the samples account for variability that might exist within the lot.

This targeted approach helps in making informed decisions based on representative data, minimizing the risk of overlooking crucial aspects of the population that might lead to errors in quality assessment.