A new medicine is intended to reduce nausea after surgery. Nausea was scored from 0 (no nausea) to 10 (the most severe nausea).
Patients with an initial score of 6 or more were put in the drug group. Patients with an initial score below 6 were put in the placebo group.
The table shows the mean nausea scores.
| Group | Mean score before treatment | Mean score after treatment |
|---|---|---|
| Drug | 7.4 | 4.6 |
| Placebo | 4.2 | 3.1 |
The researcher concluded that the drug was more effective than the placebo because the mean score decreased by more in the drug group.
Evaluate the researcher's conclusion. In your answer, suggest how the allocation of patients should be improved.
252 exam-style questions on AQA GCSE Biology 3.1 Communicable diseases, covering 3.1.1 Communicable (infectious) diseases, 3.1.2 Viral diseases, 3.1.3 Bacterial diseases, 3.1.4 Fungal diseases, 3.1.5 Protist diseases, 3.1.6 Human defence systems, 3.1.7 Vaccination, 3.1.8 Antibiotics and painkillers, and 3.1.9 Discovery and development of drugs. Each one has a worked solution and a mark scheme showing where the marks go.