Researcher: In an experiment, 500 families were given a medical self-help book, and 500 similar families were not. Over the next year, the average number of visits to doctors dropped by 20 percent for the families who had been given the book but remained unchanged for the other families. Since improved family having a medical self-help book in the home improves family health.
What this question is testing
Your task
Describe the reasoning error the argument actually commits.
Common trap
Answers that name a real logical flaw the argument doesn't actually make.
Winning move
Articulate the gap in the reasoning yourself, then match it to the choice that describes that gap.
Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.