| A | B |
|---|
| Convenience Sample | A sample consists of members of a population that are easily accessed. |
| Random Sample | Each item or person in the population is as likely to be chosen as any other. |
| Stratified Random Sample | The population is divided into similar, non-overlapping groups. A simple random sample is then selected from each group. |
| Systematic Random Sample | Every 20th person is chosen from an alphabetical list of all students attending a school. |
| Voluntary Response Sample | Students at a school who wish to express their opinions complete an online survey. |
| Biased | Convenience |
| Unbiased | Random |
| Census | All of the units within a population are included |
| Survey | Ask questions of a group of people and record the results. |
| Sample | It is some portion of a larger group |
| An unbiased sample | It is selected so that it accurately represents the entire population. |
| In a biased sample | one or more parts of the population are favored over others. |
