Scientists carried out a study to investigate a possible link between the number of alcoholic drinks adults have in a typical week and liver damage. All the adults were recruited from one town. The table shows the number of adults in each group and the number who developed liver damage during the study.
| Number of alcoholic drinks per week | Number of adults | Number who developed liver damage |
|---|---|---|
| 0–2 | 70 | 2 |
| 3–6 | 65 | 5 |
| 7–14 | 60 | 9 |
| 15 or more | 45 | 12 |
Calculate the percentage of adults who developed liver damage in the 0–2 drinks group and in the 15 or more drinks group. Give each answer to 1 decimal place.
The scientists concluded that drinking more alcohol causes liver damage.
Evaluate this conclusion using the data and the design of the study.
304 exam-style questions on AQA GCSE Biology 2.2 Animal tissues, organs and organ systems, covering 2.2.1 The human digestive system, 2.2.2 The heart and blood vessels, 2.2.3 Blood, 2.2.4 Coronary heart disease: a non-communicable disease, 2.2.5 Health issues, 2.2.6 The effect of lifestyle on some non-communicable diseases, and 2.2.7 Cancer. Each one has a worked solution and a mark scheme showing where the marks go.