Kelvin and Lewie each design surveys in order to determine the average number of people who buy food at the mall. Kelvin surveys every other person leaving the food area. Lewie surveys every fifth person leaving the mall’s main entrance. Which set of survey results is most likely to show biased results for people who buy food at the mall?
Answer
A
Kelvin’s because he surveyed people leaving an area where food is sold
B
Kelvin’s because he surveyed every other person instead of every fifth person
C
Lewie’s because he surveyed every fifth person instead of every other person
D
Lewie’s because he surveyed people who may or may not have bought food
Explanation
Kelvin surveys only people leaving the food area, so his sample is more likely to include people who bought food and may not represent everyone who buys food at the mall. Lewie surveys people leaving the main entrance, which can include both food buyers and people who did not buy food. The sampling interval—every other person versus every fifth person—is not the main source of bias.
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