Statistics Test

Simple random sample

Choosing a group from the population so that every individual has an equal chance to be picked (ie. picking names from a hat)

Self-selected sample

Members of a population can volunteer to be in the sample

Systematic sample

Rule used to select members of a population (ie. every other person)

Stratified sample

Population divided into smaller groups that share similar characteristics; a sample is then randomly selected from each group

Cluster sample

Population is divided into groups, called clusters; all members in one or more clusters are selected

Convenience sample

Only members who are easiest to reach are selected

Population

Entire group

Parameter

Data collected from the entire population

Sample

Part of a population

Statistics

Data collected from a sample, not a population

Observational study

Just observation

Experimental study

Impose treatment on a subset of a group and collect data between control and treated groups