SAT OwlQuestion bank / Evaluating statistical claims: observational studies and experiments
At a school of students, students order lunch with a new app and the other students order at the counter. Last month, students received a wrong lunch order, and of those students had ordered with the app. A parent claims that because most wrong orders came from app users, the app makes a wrong order more likely. Which of the following best evaluates the claim?
The claim is supported, because of the wrong orders came from app users.
The claim is supported, because more students use the app than order at the counter.
The claim is not supported, because wrong orders is only of all students.
The claim is not supported, because about of app users and about of counter users received a wrong order.
Show answer and explanation
Answer: D
Most wrong orders came from app users because most students use the app. To compare, use rates. Of the app users, received a wrong order, while of counter users did. App users were actually less likely to receive a wrong order.
Choice A uses the share of wrong orders from app users, which mostly reflects how many students use the app, not how likely each app user is to get a wrong order.
Why the other choices are wrong
- A. Most wrong orders came from app users because most students use the app. Compare rates instead.
- B. The number of app users explains why there are more wrong app orders, not whether the app makes errors more likely.
- C. The overall error rate doesn't compare app users with counter users.
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