Scientists followed two comparable groups of adults for 10 years. The groups lived in areas with different average levels of air pollution.
| Group | Number of adults | Number who developed lung disease |
|---|---|---|
| Lower air pollution | 6000 | 24 |
| Higher air pollution | 6000 | 42 |
Calculate the percentage increase in the risk of lung disease in the higher-air-pollution group compared with the lower-air-pollution group.
Use the data to explain why reporting only this percentage increase could give a misleading impression.
102 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.