Edexcel S2 2011 January — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2011
SessionJanuary
TopicPoisson Distribution
TypeExplain or apply conditions in context

6. Cars arrive at a motorway toll booth at an average rate of 150 per hour.
  1. Suggest a suitable distribution to model the number of cars arriving at the toll booth, \(X\), per minute.
  2. State clearly any assumptions you have made by suggesting this model. Using your model,
  3. find the probability that in any given minute
    1. no cars arrive,
    2. more than 3 cars arrive.
  4. In any given 4 minute period, find \(m\) such that \(\mathrm { P } ( X > m ) = 0.0487\)
  5. Using a suitable approximation find the probability that fewer than 15 cars arrive in any given 10 minute period.
    January 2011