To select a random sample for a population:
1. Select members at random from the target population only.
2. Eliminate samples that do not give every member of the population an equal chance of being chosen.
- Selecting every third woman entering a department store in New York does not give a random sample representing the population in Florida, since it includes members from a different target population.
- Selecting every third man entering a bar or every third person entering an opera concert does not give a random sample of the entire population because not everyone has an equal chance of being selected.