Problem-Solving and Data AnalysisVery hardEvaluating a claim about a treatment from a trial design
Problem-Solving and Data Analysis practice question
A clinic gives a new sleep treatment to 50 patients who asked for it and compares their sleep with 50 patients who did not ask. The treated group sleeps better. Which change to the design would most strengthen the conclusion that the treatment works?
- A. Assigning patients to the treatment or to no treatment at randomCorrect
- B. Increasing both groups to 60 patients
- C. Measuring sleep with a different questionnaire
- D. Treating all 100 patients
Answer: A. Assigning patients to the treatment or to no treatment at random
Random assignment removes the difference between those who ask and those who do not.
Why the other answers are wrong
- B. Increasing both groups to 60 patients
- A larger biased sample is still biased.
- C. Measuring sleep with a different questionnaire
- The measure is not the flaw.
- D. Treating all 100 patients
- No comparison group would remain.
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