A-LevelBiologyInfectious diseasesOct/Nov 2017Paper 1 Q381 Mark
A scientist investigated the effect of an antibiotic on the treatment of cholera. 320 people suffering with cholera were split into two groups. One group was treated with an antibiotic while the other group was not given antibiotics. Both groups were given fluids containing sugars and mineral salts (oral rehydration therapy). The scientist recorded the number of days that each person suffered from diarrhoea. The table shows the results. [Figure 38.1 - table of mean time suffering from diarrhoea for different treatments] What is the percentage decrease in the mean time that a person suffered from diarrhoea when they were treated with the antibiotic?
A39.6%
B60.4%
C165.6%
D252.4%
✓ Correct Answer
The correct answer is A: 39.6%
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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