If the sampling procedure used whole classrooms as sampling units the method is called

If the sampling procedure used whole classrooms as sampling units the method is called

• A. Simple random sampling
• B. Stratified sampling
• C. Systematic sampling
• D. Cluster sampling

Answer: (D)

The concept being tested is using naturally occurring groups as the sampling units, which is called cluster sampling. When whole classrooms are used as sampling units, you’re selecting a sample of groups (classrooms) rather than individual students. Then you study all students within the chosen classrooms (or you sample within those classrooms, depending on the design). This differs from simple random sampling, where individuals are chosen from the entire population with equal chance; from stratified sampling, where the population is divided into subgroups and samples are taken from each subgroup to ensure representation; and from systematic sampling, where units are selected at regular intervals from a list. Cluster sampling is especially efficient when the population is large and dispersed, because it reduces travel and listing costs by concentrating data collection within a few selected groups, though it can introduce more sampling error if students within a classroom are more similar to each other than to students in other classrooms.

The concept being tested is using naturally occurring groups as the sampling units, which is called cluster sampling. When whole classrooms are used as sampling units, you’re selecting a sample of groups (classrooms) rather than individual students. Then you study all students within the chosen classrooms (or you sample within those classrooms, depending on the design). This differs from simple random sampling, where individuals are chosen from the entire population with equal chance; from stratified sampling, where the population is divided into subgroups and samples are taken from each subgroup to ensure representation; and from systematic sampling, where units are selected at regular intervals from a list. Cluster sampling is especially efficient when the population is large and dispersed, because it reduces travel and listing costs by concentrating data collection within a few selected groups, though it can introduce more sampling error if students within a classroom are more similar to each other than to students in other classrooms.