(a)[2]
Find the probability that they go to the park on at most $5$ of the next $7$ days.
(b)[2]
Find the probability that the dog barks on a given day.
(c)[1]
Find the variance of the number of times they visit the park over $30$ days.
Mathematics 9709 · AS & A Level · The Poisson distribution
The Poisson distribution — practice question
Every day, Christa walks her dog. On any day, the chance that they visit the park is $0.6$. When they do go to the park, the probability that the dog barks is $0.35$. When they do not go to the park, the probability that the dog barks is $0.75$.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “The sum of 2 or 3 binomial probabilities written as ${}^{7}C_r(0.6)^r(0.4)^{7-r}$” …
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