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STRATIFIED SAMPLING

PRESENTED BY

SARA PAUL

I M.ED

NSSTC

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DEFINITION

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Stratified sampling is a type of sampling method in which the total population is divided into smaller groups or strata to complete the sampling process. The strata is formed based on some common characteristics in the population data.

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PROPORTIONATE STRATIFIED RANDOM SAMPLE�

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The size of each stratum is proportionate to the population size of the strata. This means each stratum has the same sampling fraction.

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DISPROPORTIONATE STRATIFIED RANDOM SAMPLE

The different strata do not have the same sampling fractions as each other.

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�ADVANTAGES OF STRATIFIED SAMPLING

  • Always achieve greater precision
  • More convenient
  • Smaller in size
  • Guarantees better coverage of the population.

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DISADVANTAGES OF STRATIFIED SAMPLING

  • Difficult to identify appropriate strata for study.
  • More complex to organize and analyze the result.

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