Question

If you were told that four students from a class of twenty were questioned for a poll about study habits, this would be an example of ________________.

Answer 1

Answer is: strata (stratified sampling).
Stratified sampling is a method when statistics use sample from a population.
The strata must have two characteristics:
1. mutually exclusive - all elements in the population must be appointed to only one stratum.
2. collectively exhaustive-no population element can be excluded from stratum.