stratified sample

Meaning

1. 1nouncountable

   A sample chosen by first dividing a population into separate groups, then picking members from every group in proportion to its size.

   Grammar: Countable: a stratified sample, two stratified samples.

   Patterns

   • draw a stratified sample
   • a stratified sample of something

   The researchers took a stratified sample of 500 students, with equal numbers from each year.

   A stratified sample guarantees that small groups are not missed.

   To survey the town fairly, we used a stratified sample based on age and income.

Word forms

Common combinations

draw a stratified sample

The statistician drew a stratified sample from the voter list.

proportional stratified sample

A proportional stratified sample matches the group sizes in the population.

use a stratified sample

The poll used a stratified sample to reflect each region.

stratified sample of the population

They surveyed a stratified sample of the population.

Synonyms and how they differ

quota sample

A quota sample fills set numbers from groups but without random selection, so it is less reliable than a stratified sample.

random sample

A random sample picks members purely by chance, so small groups may be missed, unlike in a stratified sample.

cluster sample

A cluster sample picks whole groups at random and studies everyone inside, while a stratified sample draws from every group.

Opposites

Word family

stratify verb

to arrange or divide into layers or groups

stratification noun

the process of dividing into layers or groups

stratum noun

one group or layer in a population

strata noun

plural of stratum

Commonly confused: stratified sample or random sample?

Practice

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