Mathematics 9709 · AS & A Level · The Poisson distribution

The Poisson distribution — practice question

On average, among people who enter this large shop, 34% leave without buying anything, 53% spend less than $50, and 13% spend at least $50.
(i)[3]

A random group of 15 shop visitors is selected. Calculate the probability that 14 or more of them buy something.

(ii)[3]

From $n$ randomly chosen shop visitors, the probability that none of them spends at least $50 is below 0.04. Find the smallest possible value of $n$.

Worked solution & mark scheme

This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: Identification of a binomial distribution with parameters $n=15$, $p=0.66$

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