What is the best way to ensure that results of a study are generalizable to a population?

The first national government for the united states was

What statement shows that the agreement between the fictional nations of ziberia and deerkey is a free trade agreement?

Which situation is the best example of regulation in an economic system? a retail business just opened a new store in a community close to its original location. a small clothing shop slashed it prices to attract customers from a larger department store nearby. a farmers’ market has offered a special deal to customers from a nearby yoga school. a state agency has been created to monitor the production and distribution of sports drinks.