CAIE S2 2015 November — Question 1

Exam BoardCAIE
ModuleS2 (Statistics 2)
Year2015
SessionNovember
TopicLinear combinations of normal random variables
TypeDistribution of sample mean

1 It is known that the number, \(N\), of words contained in the leading article each day in a certain newspaper can be modelled by a normal distribution with mean 352 and variance 29. A researcher takes a random sample of 10 leading articles and finds the sample mean, \(\bar { N }\), of \(N\).
  1. State the distribution of \(\bar { N }\), giving the values of any parameters.
  2. Find \(\mathrm { P } ( \bar { N } > 354 )\).