EXAMPLE 14 Stratified sampling
LeBron James, of the Cleveland Cavaliers.
A researcher is interested in analyzing whether differences in scoring exist among the basketball teams in the three divisions of the Eastern Conference of the National Basketball Association (Table 10). Obtain a stratified sample of two teams from each division.
Table 1.22: TABLE 10 Teams in the three divisions of the Eastern Conference of the National Basketball Association
| Atlantic Division | Central Division | Southeast Division |
|---|---|---|
| Boston Celtics | Chicago Bulls | Atlanta Hawks |
| Brooklyn Nets | Cleveland Cavaliers | Charlotte Bobcats |
| New York Knicks | Detroit Pistons | Miami Heat |
| Philadelphia 76ers | Indiana Pacers | Orlando Magic |
| Toronto Raptors | Milwaukee Bucks | Washington Wizards |
Solution
A random sample of size two was drawn from the teams in each of the three divisions. These six teams are then combined to form our stratified sample of basketball teams. Note that each random sample is different, as yours will be.
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NOW YOU CAN DO
Exercises 15–18.