Interpreting health data and risk perceptionEdexcel International A Level Biology: Subtopic test

1. 1
   A health authority publishes mortality data for a disease. In 2010 there were 1,200 deaths from the disease in a population of 2,400,000 people. In 2020 there were 900 deaths in a population of 3,000,000 people.

   (a)

   What is meant by the term mortality?

   [1 mark]

   • AThe number of people living with a disease
   • BThe number of new cases of a disease each year
   • CThe proportion of people with a risk factor
   • DThe number of deaths from a disease in a population over a given time

   (b)

   What was the mortality rate from the disease in 2010?

   [1 mark]

   • A50 per 100,000 people
   • B500 per 100,000 people
   • C5 per 100,000 people
   • D1,200 per 100,000 people

   (c)

   Calculate the percentage change in the mortality rate between 2010 and 2020.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A study of the link between a type of fast food and heart disease recruited 60 volunteers, all of whom were students at one university. The researchers asked the volunteers to record what they ate for one week and then measured their blood pressure.

   (a)

   What is the main weakness in the way the sample was chosen?

   [1 mark]

   • AThe sample is too large to analyse
   • BVolunteers were not randomly allocated to groups
   • CIt is small and is not representative of the general population
   • DStudents will not agree to take part

   (b)

   Which statement correctly defines the reliability of a study?

   [1 mark]

   • AThe study measures what it claims to measure
   • BSimilar results are obtained when the study is repeated
   • CThe results prove that one factor causes another
   • DThe sample is representative of the population

   (c)

   Suggest two changes to the sample that would allow the conclusions to be applied more confidently to the general population.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A study followed 100,000 adults for 12 years. Of the 20,000 adults who ate fewer than two portions of fruit and vegetables each day, 800 developed cardiovascular disease (CVD). Of the 20,000 adults who ate five or more portions each day, 500 developed CVD. The remaining adults ate between two and five portions each day. The diets were recorded by the adults themselves in questionnaires.

   (a)

   Calculate the percentage reduction in the incidence of CVD in the group eating five or more portions each day compared with the group eating fewer than two portions.

   [3 marks]

   (b)

   A newspaper headline states that eating five portions of fruit and vegetables a day prevents CVD. Evaluate this claim using the information about the study.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Surveys show that many adults fear rare events, such as air travel, more than common causes of death such as CVD, which accounts for roughly a quarter of all deaths in the country. Health authorities collect illness and mortality data and run campaigns that try to change people's behaviour.

   (a)

   Explain why people's perceived risk of a disease can differ from the actual risk, and why this matters for public health.

   [6 marks]

   (b)

   Explain how the choice of sample, the sample size and the control of variables affect how far the findings of a health study can be trusted, and suggest why different studies may give conflicting evidence.

   [6 marks]

   Total for question 4: 12 marks

End of questions