Bluebook SAT Test Evaluating Statistical Claims: Observational Studies and Experiments 8

Question 1

A study randomly assigns 300 adults to participate in a strength training program or a stretching-only program. After 12 weeks, the strength training group shows greater bone density. The researcher concludes strength training causes increased bone density. Which additional question is most important for evaluating this conclusion?

Accepted Answer

Are the study participants representative of the broader adult population of interest?

Answer

While the randomized design supports causation within the study, you must consider whether the participants represent the target population to assess whether results can be generalized.

Question 2

A poll of 1,200 randomly selected U.S. voters finds that 54% favor a specific immigration policy. Which conclusion is best supported?

Accepted Answer

A majority of U.S. voters likely favor this policy, subject to a margin of error.

Answer

A random sample supports a generalization about the broader voting population, but the result is an estimate with uncertainty (margin of error), not a precise count or a prediction of outcomes.

Question 3

A researcher notices that ice cream sales and drowning rates are highly correlated throughout the year. She concludes that ice cream causes drowning. What is the most likely explanation for this correlation?

Accepted Answer

A confounding variable — hot weather — increases both ice cream sales and swimming (and therefore drowning).

Answer

Hot weather increases both ice cream consumption and swimming frequency, creating a spurious correlation between ice cream and drowning that has no causal mechanism.

Question 4

A randomized clinical trial shows that Drug X reduces migraines better than a placebo in a diverse national sample of 2,000 adults. A neurologist concludes that Drug X should be the first-line treatment for all adults with migraines. Which statement about this conclusion is correct?

Accepted Answer

The conclusion is reasonable but should be further evaluated against side effects, cost, and results in subgroups.

Answer

Even strong randomized trial evidence supports — but does not fully determine — treatment decisions; real-world factors like side effects, cost, and subgroup differences must also be evaluated.

Question 5

A high school conducts an experiment where 10 volunteering teachers adopt a new grading method and their students are compared to students of non-participating teachers. Students in the new grading method classes earn higher grades. What is the most significant flaw?

Accepted Answer

Teachers who volunteered may be more skilled or motivated, confounding the relationship between grading method and grades.

Answer

Volunteer teachers may be more effective or motivated regardless of the grading method, making teacher quality a confounding variable in this observational design.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Evaluating Statistical Claims: Observational Studies and Experiments 8