P-Chapter: What is Statistics?
Ticket Out The Door
Answer the following question using what you have learned about data collection.
Late in 2004, baseball superstar Barry Bonds admitted using creams and ointments that contained steroids.
Bonds said he didn’t know that these substances contained steroids. A Gallup Poll asked a random sample of U.S.
adults whether they thought Bonds was telling the truth: 42% said “probably not” and 33% said “definitely not.”
1.
Why did Gallup survey a random sample of U.S. adults rather than a sample of people attending a Major
League Baseball game?
By opening the population to all U.S. adults, Gallup is hoping to avoid preferential responses. Fans at a
Major League Baseball game could favor Bonds because he is a player or oppose him because of his alleged
abuse of steroids.
2. If Gallup had survey all U.S. adults instead of a sample, about what percent of the responses would be
“probably not”? “Definitely not”? Explain.
We would expect 42% of all U.S. adults to say “probably not” and 33% to say “definitely not.” This is
because Gallup took a random sample of all U.S. adults. As a result, the results of the sample should be
representative of those from the population.
3. Can we conclude based on these results that Barry Bonds is lying? Why or why not?
No such conclusion should be drawn. This survey represents only the opinions of the public.