A-LevelMathematicsProbability and statisticsMay/June 2025Paper 6 Q27 Marks
The lengths of pencils made at a factory are normally distributed. The standard deviation of the lengths is σcm, and the mean is supposed to be 10cm. An inspector thinks that the mean is actually greater than 10cm. He takes a random sample of 50 pencils produced at the factory and finds that the mean of these 50 lengths is 10.03 cm. He then carries out a hypothesis test.
📋 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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