Question

cluster spampling

Answer 1

Cluster sampling: A cluster sampling refers to a type of sampling method in which the researcher divides the population into separate groups, called clusters and then a simple random sample of clusters is selected from the population. The elements in each cluster are then sampled.

When all the elements in each sampled cluster are sampled, then it is called a "one-stage" cluster sampling plan and when simple random sub sample of elements is selected within each of these groups then it is called as a "two-stage" cluster sampling plan. For a fixed sample size, the expected random error is smaller when most of the variation in the population is present internally within the groups, and not between the groups.