PSY 250 Lecture Notes - Lecture 13: Simple Random Sample, Stratified Sampling, Cluster Sampling
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Divided into strata (segments/groups) based on a characteristic. The smaller the strata, the more homogeneous the sample. Same size in each segment is proportional to the segment size in the population. Sample size in each segment is not proportional to the segment size in the population. Individuals are chosen at random from groups within a population. Cluster samples allow researchers to obtain a probability sample from a large population more easily than they would with a simple random sample, because the list from which individuals are selected is more manageable and easier to obtain. Groups are randomly sampled from the population. Using second criteria sample individuals from randomly selected clusters. Probability of choosing an individual is not known. Not all members of the population are considered for participation. Sample is made up from available individuals. Most common example is using student volunteers as subjects for the research.
