OCR MEI S2 2012 January — Question 2

Exam BoardOCR MEI
ModuleS2 (Statistics 2)
Year2012
SessionJanuary
TopicPoisson Distribution
TypeState conditions only

2 The number of printing errors per page in a book is modelled by a Poisson distribution with a mean of 0.85 .
  1. State conditions for a Poisson distribution to be a suitable model for the number of printing errors per page.
  2. A page is chosen at random. Find the probability of
    (A) exactly 1 error on this page,
    (B) at least 2 errors on this page. 10 pages are chosen at random.
  3. Find the probability of exactly 10 errors in these 10 pages.
  4. Find the least integer \(k\) such that the probability of there being \(k\) or more errors in these 10 pages is less than \(1 \%\). 30 pages are chosen at random.
  5. Use a suitable approximating distribution to find the probability of no more than 30 errors in these 30 pages.