MATH 124 Lecture Notes - Lecture 2: San Francisco State University, Stratified Sampling, Cluster Sampling
Document Summary
It is used when each element of the population is to be given the same opportunity to be chosen in the sample: stratified sampling. This is used when it is known in advance that the population is divided into strata, which are equivalent to categories and which are generally not of equal size. A random sample is then drawn from each stratum, usually proportional to the size of the stratum: cluster sampling in this case the population is divided into groups called clusters. Then a certain number of them are chosen at random and all the elements of the chosen clusters form the sample: systematic sampling. This is used when the population data are ordered in numerical form. The first observation is chosen at random from the first elements of the population and the following observations are chosen with the same distance between them. Ways to collect data: conducting personal interviews.
