Bluebook SAT Test Evaluating Statistical Claims: Observational Studies and Experiments 12

Question 1

A study finds that employees who use ergonomic chairs report fewer back problems than those who use standard chairs. Participants chose which chair to use. A company concludes that providing ergonomic chairs will reduce employee back problems. What is the primary concern with this conclusion?

Accepted Answer

Employees who chose ergonomic chairs may have been more health-conscious and engaged in other practices that reduce back problems.

Answer

Self-selection into chair type creates a confound; employees who seek out ergonomic chairs may also exercise more or take other preventive actions.

Question 2

Researchers randomly assign 250 participants to a mindfulness program and 250 to a control group (waiting list) for 8 weeks, then measure anxiety levels. The mindfulness group shows significantly lower anxiety. To which group can the results best be generalized?

Accepted Answer

People similar to those who enrolled in the study

Answer

Generalizability is determined by how the sample was selected; the results apply most directly to people similar to those who enrolled, not to all people with anxiety.

Question 3

A newspaper reports that people who drink wine with dinner have lower rates of heart disease. The report concludes that wine consumption prevents heart disease. Which of the following best identifies the flaw in this reasoning?

Accepted Answer

Wine drinkers may differ from non-wine drinkers in diet, income, or lifestyle in ways that affect heart health.

Answer

People who drink wine with dinner may have generally healthier Mediterranean diets and higher incomes—factors that independently reduce heart disease risk.

Question 4

A randomized experiment tests whether a new reading program improves literacy scores. Students are randomly assigned to the program or a control group. At the end of the year, the program group scores significantly higher. Which statement is most accurate?

Accepted Answer

The reading program caused improved literacy scores in this experiment.

Answer

Random assignment supports a causal conclusion for the study sample; broader generalizability requires evidence that the sample represents the broader population.

Question 5

A research team observes that neighborhoods with community gardens have lower rates of childhood obesity. A city planner proposes building community gardens to reduce childhood obesity. Which type of evidence would most strengthen the causal claim?

Accepted Answer

A randomized experiment in which neighborhoods are randomly assigned to receive a community garden or not

Answer

Only random assignment of neighborhoods to conditions can control for the many ways that neighborhoods with and without community gardens may already differ.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Evaluating Statistical Claims: Observational Studies and Experiments 12