A-LevelMathematicsProbability and statistics9709/63 · May/June 2025 · Q44 Marks
Emma needs to choose one person at random from three people, P, Q and R. She plans to throw two fair coins and note the number, n, of heads. If n is 0, she will choose P. If n is 1, she will choose Q. If n is 2, she will choose R.
- (a)By considering probabilities, show that the choice made by this method is not random.[2]
- (b)Describe how Emma could use a single throw of a fair six-sided dice to make this random choice.[2]
Mark scheme
Marking points from the official mark scheme (May/June 2025). The mark or mark type is shown in brackets.
- [B1] OE. SOI.
- [B1] Numerical justification or there is one way to get 0 but two ways to get 1, or similar B1B1.
- [B1] Identifying the three correct cases to choose or reject and correctly identifying choosing or rejecting.
- [B1] OE. Using the score on the dice to give each of the three cases equal probability. More than one throw of the dice scores B0B0.
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