Cluster sampling is a sampling technique used when "natural" but relatively homogeneous groupings are evident in a statistical population. It is often used in marketing research. In this technique, the total population is divided into these groups (or clusters) and a simple random sample of the groups is selected. Then the required information is collected from a simple random sample of the elements within each selected group. This may be done for every element in these groups or a subsample of elements may be selected within each of these groups. A common motivation for cluster sampling is to reduce the average cost per interview. Given a fixed budget, this can allow an increased sample size. Assuming a fixed sample size, the technique gives more accurate results when most of the variation in the population is within the groups, not between them.
Read more about Cluster Sampling: Cluster Elements, Aspects of Cluster Sampling, Advantage, Disadvantage
Famous quotes containing the word cluster:
“In a sense the world dies every time a writer dies, because, if he is any good, he has been a wet nurse to humanity during his entire existence and has held earth close around him, like the little obstetrical toad that goes about with a cluster of eggs attached to his legs.”
—E.B. (Elwyn Brooks)