2020HSCShort answer

Q27 (a)

2 marks

Question

Exposure to arsenic in drinking water has been associated with the onset of many diseases. The World Health Organisation recommends arsenic levels in drinking water should be below 10 µg L–1.
An epidemiological study involving 58 406 young adults was conducted over an 11-year period in one country to investigate young-adult mortality due to chronic exposure to arsenic in local drinking water. Each individual’s average exposure and cumulative exposure to arsenic over the time of the study were calculated. Age, sex, education and socioeconomic status were taken into account during the analysis of the results.
The graphs show survival rates for males and females over the 11-year period associated with different average levels of exposure to arsenic in drinking water.

Identify TWO features of the method used that contributed to the validity of this study.

Uncropped source page 22 for question 27.a; requires human review and cropping — Reviewed visual · source page 22

Try the question before revealing the answer.

Solution

Criteria	Marks
• Identifies TWO features that contribute to the validity of the study	2
• Identifies ONE feature that contributes to the validity of this study	1

Sample answer:

Factors which contribute to the validity of the study could include:

Age
Sex
Arsenic exposure
Large sample size
Socioeconomic status

Supplied marking guidance · human reviewed

Compare this with your working, not only your final sentence.

Syllabus alignment

Module 8 · Non-infectious Disease and Disorders

EpidemiologyEvaluate the method used in an epidemiological study.

Spot a problem? Send feedback