Mathematics 9709 · AS & A Level · The Poisson distribution
The Poisson distribution — practice question
Ana sees her friends every day. On any given day, the chance that she arrives early is $0.05$, while the chance that she arrives late is $0.75$. In all other cases, she is on time.
(a)[5]
Determine the probability that she is on time on fewer than 20 of the next 96 days.
(b)[4]
When she is early, the probability that she eats a banana is $0.7$. When she is late, she does not eat a banana. When she is on time, the probability that she eats a banana is $0.4$. For one specific meeting with friends, she does not eat a banana; determine the probability that she is on time.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Recognising $p=0.2$ and working out $\mu=19.2$, $\sigma^2=15.36$” …