Scientists carried out an observational study of four comparable groups of adults for the same length of time.
| Group | Viral infection | Obesity | Cases of liver disease per 1000 adults |
|---|---|---|---|
| J | Absent | Not obese | 12 |
| K | Present | Not obese | 36 |
| L | Absent | Obese | 30 |
| M | Present | Obese | 90 |
Which conclusion is best supported by the data?
Viral infection is associated with three times the rate and obesity with 2.5 times the rate; the study does not establish causation.
Viral infection is associated with three times the rate and obesity with 2.5 times the rate; the study shows that both are causes.
Viral infection is associated with 2.5 times the rate and obesity with three times the rate; the study does not establish causation.
Viral infection is associated with 2.5 times the rate and obesity with three times the rate; the study shows that both are causes.
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.