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Exposure to arsenic in drinking water has been associated with the onset of many diseases - HSC - SSCE Biology - Question 27 - 2020 - Paper 1
Question 27
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 ... show full transcript
Worked Solution & Example Answer:Exposure to arsenic in drinking water has been associated with the onset of many diseases - HSC - SSCE Biology - Question 27 - 2020 - Paper 1
Step 1
Identify TWO features that contribute to the validity of the study
Answer
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Sample Size: The study involves a large sample size of 58,406 young adults, which enhances the reliability of the results and allows for more generalizable conclusions.
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Age, Sex, and Socioeconomic Status Control: The study took into account various demographic factors, including age, sex, and socioeconomic status, which can help in understanding their potential effects on the study's outcomes and thus contribute to its validity.
Step 2
Step 3
Discuss the findings related to the hypothesis
Answer
Survival rates are highest for those exposed to less than 90 µg L^{-1} arsenic in both males and females. This group serves as a control, suggesting that the majority of participants in the study survived over the 11-year period.
In both sexes, increasing doses of arsenic lead to decreased survival, indicating that arsenic exposure is correlated with a decline in survival rates. The research suggests that as exposure levels increase, survival decreases, thereby supporting the hypothesis that higher arsenic levels may contribute to mortality.
Survival appeared to decline progressively over the 11 years, creating the notion that the increasing exposure to arsenic is indeed causing a detrimental impact on survival. Significant to note, the differences in survival rates between the lowest and higher exposure groups were relatively small, only varying by 0.1% or less.