CAIE S2 2004 November — Question 5

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2004
SessionNovember
TopicPoisson Distribution
TypeFinding minimum n for P(X=0) threshold

5 Of people who wear contact lenses, 1 in 1500 on average have laser treatment for short sight.
  1. Use a suitable approximation to find the probability that, of a random sample of 2700 contact lens wearers, more than 2 people have laser treatment.
  2. In a random sample of \(n\) contact lens wearers the probability that no one has laser treatment is less than 0.01 . Find the least possible value of \(n\).