A research team developed a cream containing a new medicine for a skin condition that causes itching. A lower itching score means less severe symptoms.
In a trial, 300 patients were put at random into two equal groups. All the patients completed the 8-week trial. One group used the medicine cream and the other group used a placebo cream. Neither the patients nor the doctors recording the itching scores knew which cream each patient used.
| Group | Mean itching score at the start | Mean itching score after 8 weeks | Number of patients reporting side effects |
|---|---|---|---|
| Medicine cream | 7.6 | 3.8 | 32 |
| Placebo cream | 7.5 | 5.9 | 6 |
The researchers issued a statement saying that the medicine was effective and safe.
Explain what the trial evidence suggests about whether the medicine is effective.
Explain why scientists should be cautious about accepting the statement that the medicine is safe.
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.