To stratify is to group a heterogenous population into homogenous sub-groups that have common characteristics. Therefore, Stratified sampling techniques are generally used when the population is heterogeneous, or dissimilar or where certain homogeneous, or similar, sub-populations can be isolated. Stratified sampling does not operate on its own. Once you stratify, you then need to simple random within the strata.

This lesson will discuss:

1. The meaning of stratified random sampling design
2. Steps followed when using stratified random sampling design; 
3. Strengths and limitations of stratified random sampling design.