It divides the population in homogeneous subpopulations or strata, depending on characteristics. Each member should be assigned exactly only one stratum.

To obtain a sample that best represents the entire population

• Imbalanced data
• Reducing the overall variance
• Ensuring diversity in the sample

• Unable to classify every member of the population in a unique strata

• Unique strata
• Every member of the population should be assigned a strata

• Any dataset containing categorical variables.

• A sample best representing the population.

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• Members are classified into multiple categories.
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