Statistics Tip of the Week: Stratified Sampling can improve accuracy when the Proportions of a population are known.
Randomness is likely to be representative, and Simple Random Sampling (SRS) can often be the most effective way to achieve it. But in certain situations, other methods such as Systematic, Stratified, and Clustered Sampling may have an advantage.
Stratified Sampling can be used when we know the Proportions of homogeneous groups which make up the population.
Advantage: Stratified Sampling avoids selecting a Sample which is not representative -– at least with regard to the Proportions of the homogenous groups.
Disadvantage: It can't be used when there are no homogeneous groups.
Andrew A. (Andy) Jawlik is the author of the book, Statistics from A to Z -- Confusing Concepts Clarified, published by Wiley.