Mathematics 9709 · AS & A Level · The Poisson distribution

The Poisson distribution — practice question

The chance that Sue finishes a Sudoku puzzle correctly is $0.75$.
(i)[3]

Sue works through $n$ Sudoku puzzles. Determine the smallest value of $n$ for which the chance that she gets every one of the $n$ puzzles correct is below $0.06$.

(ii)[3]

Every month Sue attempts $14$ Sudoku puzzles. Let $X$ represent the number she solves correctly. Determine the value of $X$ with the greatest probability. You may assume that this value is one of the two values nearest to the mean of $X$.

(iii)[5]

Find the probability that Sue completes more than $11$ Sudoku puzzles correctly in exactly $3$ of the next $5$ months.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: The inequality $(0.75)^n < 0.06$ is correct (or an equivalent form)

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