How to answer it
- Ask whether subjects were randomly assigned to groups.
- Ask whether they were randomly sampled, and from what population.
- Allow a causal claim only with random assignment, and only for people like those studied.
Worked example
An original question in the SAT format, already answered.
SAT MathWorked example
Researchers randomly assigned 300 volunteers to drink either green tea or water every day for a month. The green tea group reported better sleep.
Which conclusion is best supported?
- AGreen tea improves sleep for all adults.
- BGreen tea likely caused better sleep among people like these volunteers.
- CPeople who choose to drink tea sleep better.
- DNo conclusion is possible because the sample is too small.
Answer: B. Random assignment supports a causal conclusion, but the volunteers weren’t a random sample of all adults, so it applies to people like them.
The most common trap
Generalizing past the sample. Volunteers aren’t a random sample of everyone.
Practice it
Hourly Prep’s daily sets mix evaluating statistical claims with the rest of SAT Math, and send more of it your way when it’s a weak spot. See how the SAT prep plan works, or browse the other SAT skill guides.