A-LevelMathematicsProbability and statisticsMay/June 2023Paper 5 Q512 Marks
The lengths of Western bluebirds are normally distributed with mean 16.5cm and standard deviation 0.6 cm. A random sample of 150 of these birds is selected. The lengths of Eastern bluebirds are normally distributed with mean 18.4cm and standard deviation σcm. It is known that 72% of Eastern bluebirds have length greater than 17.1 cm. A random sample of 120 Eastern bluebirds is chosen.
📋 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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