| A | B |
|---|
| Subject | Person from whom data are collected |
| Participant | Person from who data are collected |
| Sample | Group of subjects or participants from whom data are collected |
| Population | A larger group to whom results can be generalized |
| Probability sampling | Known probability of selection from the population |
| Simple random sampling | Each member of the population has the same probability of being selected |
| Systematic sampling | Every nth member of the population is selected |
| Stratified sampling | Subjects are selected from strata or groups of the population |
| Proportional Stratified sampling | Reflects prooportion of stratum in populaation |
| Disproportional sampling | Number of subjects in each strata does not reflect proportion in population |
| Cluster Sampling | Naturally occurring groups are selected |
| Nonprobability sample | Probability of selection not known |
| Convenience sample | Nonprobability availiable |
| Quota sampling | Nonrandom sampling representative of a target populartion |
| Purposive sampling | Selection of particulary informative or useful subjects |
| Typical case sampling | Selecting representative participants |
| Extreme case sampling | Selecting unique or atypical participants |
| Maximum variation sampling | Selecting participants to represent extreme cases |
| Snowball sampling | Selecting participants from recommendations of other participants |
| Critical case sampling | Selecting the most important participants to understand phenomena being studied |
