CAIE S2 2020 November — Question 5

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2020
SessionNovember
TopicPoisson Distribution
TypeState conditions only

5 Customers arrive at a shop at a constant average rate of 2.3 per minute.
  1. State another condition for the number of customers arriving per minute to have a Poisson distribution.
    It is now given that the number of customers arriving per minute has the distribution \(\mathrm { Po } ( 2.3 )\).
  2. Find the probability that exactly 3 customers arrive during a 1 -minute period.
  3. Find the probability that more than 3 customers arrive during a 2 -minute period.
  4. Five 1-minute periods are chosen at random. Find the probability that no customers arrive during exactly 2 of these 5 periods.