In a study, 18 of 300 untreated patients and 12 of 400 treated patients have a heart attack. The groups are comparable and are followed for the same time.
What is the percentage reduction in heart attack risk in the treated group compared with the untreated group?
33.3%33.3\%33.3%
25.0%25.0\%25.0%
50.0%50.0\%50.0%
3.0%3.0\%3.0%
44 exam-style questions on Edexcel GCSE Biology 5.4 Non-communicable diseases, covering 5.4.1 Interaction of factors in non-communicable disease, 5.4.2 Lifestyle factors and non-communicable disease, and 5.4.3 Treatments for cardiovascular disease. Each one has a worked solution and a mark scheme showing where the marks go.