OCR Further Statistics AS 2019 June — Question 2

Exam BoardOCR
ModuleFurther Statistics AS (Further Statistics AS)
Year2019
SessionJune
TopicPoisson Distribution
TypeMultiple independent time periods

2 On any day, the number of orders received in one randomly chosen hour by an online supplier can be modelled by the distribution \(\operatorname { Po } ( 120 )\).
  1. Find the probability that at least 28 orders are received in a randomly chosen 10 -minute period.
  2. Find the probability that in a randomly chosen 10-minute period on one day and a randomly chosen 10-minute period on the next day a total of at least 56 orders are received.
  3. State a necessary assumption for the validity of your calculation in part (b).