CAIE S2 2017 June — Question 5

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2017
SessionJune
TopicApproximating the Poisson to the Normal distribution
TypeMultiple approximations in one question

5
  1. A random variable \(X\) has the distribution \(\operatorname { Po } ( 42 )\).
    (a) Use an appropriate approximating distribution to find \(\mathrm { P } ( X \geqslant 40 )\).
    (b) Justify your use of the approximating distribution.
  2. A random variable \(Y\) has the distribution \(\mathrm { B } ( 60,0.02 )\).
    (a) Use an appropriate approximating distribution to find \(\mathrm { P } ( Y > 2 )\).
    (b) Justify your use of the approximating distribution.