Types of Sample(Statistics)

Cluster random sample: The population is first split into groups. The overall sample consists of every member from some of the groups. The groups are selected at random.

Example—An airline company wants to survey its customers one day, so they randomly select 5 flights that day and survey every passenger on those flights.

Convenience sample: The researcher chooses a sample that is readily available in some non-random way.

Example—A researcher polls people as they walk by on the street.

Stratified random sample: The population is first split into groups. The overall sample consists of some members from every group.

Example—A student council surveys 100 students by getting random samples of 25 freshmen, 25 sophomores, 25 juniors and 25 seniors.

Simple random sample: Every member and set of members has an equal chance of being included in the sample.

Example—A teachers puts students' names in a hat and chooses without looking to get a sample of students.

Systematic random sample: Members of the population are put in some order. A starting point is selected at random, and every nth is chosen

Example—A principal takes an alphabetized list of student names and picks a random starting point. Every 20th student is selected to take a survey