CAIE S2 2017 March — Question 3

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2017
SessionMarch
TopicCentral limit theorem

3 The length, in centimetres, of a certain type of snake is modelled by the random variable \(X\) with mean 52 and standard deviation 6.1. A random sample of 75 snakes is selected, and the sample mean, \(\bar { X }\), is found.
  1. Find \(\mathrm { P } ( 51 < \bar { X } < 53 )\).
  2. Explain why it was necessary to use the Central Limit theorem in the solution to part (i).