SAT OwlQuestion bank / Evaluating statistical claims: observational studies and experiments
A school district wants to determine whether a new reading program improves reading scores for the fourth-grade students in the district. Which of the following study designs would allow the district both to generalize the results to all fourth graders in the district and to conclude that the program causes any improvement?
Select a random sample of fourth graders and give all of them the program, then compare their scores with last year's scores.
Ask for fourth-grade volunteers and randomly assign half of them to use the program.
Select a random sample of fourth graders and let each student choose whether to use the program.
Select a random sample of fourth graders and randomly assign half of them to use the program.
Show answer and explanation
Answer: D
Generalizing to all fourth graders in the district requires random selection from that population. Concluding cause and effect requires random assignment to the program and a comparison group. Only choice D has both.
Choice B uses random assignment, which supports causation, but volunteers may not represent all fourth graders in the district.
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