easy · GMAT Verbal

Which of the following is an example of an unrepresentative sample?

1. Selecting 500 people at random from a city's full phone directory for a local opinion poll.
2. Surveying only professional athletes to determine the average fitness level of the general population.
3. Surveying 1,000 randomly selected eligible voters from across the entire nation about an election.
4. Measuring a randomly chosen subset of items from a large shipment to estimate the entire shipment's quality.
5. Testing every tenth finished product as it moves along an assembly line in order to detect manufacturing defects.

Sign up free to see the explanation and track your rank →