Edexcel S4 2002 June — Question 1

Exam BoardEdexcel
ModuleS4 (Statistics 4)
Year2002
SessionJune
TopicWilcoxon tests

  1. The random variable \(X\) has an \(F\) distribution with 10 and 12 degrees of freedom. Find \(a\) and \(b\) such that \(\mathrm { P } ( a < X < b ) = 0.90\).
    (3)
  2. A chemist has developed a fuel additive and claims that it reduces the fuel consumption of cars. To test this claim, 8 randomly selected cars were each filled with 20 litres of fuel and driven around a race circuit. Each car was tested twice, once with the additive and once without. The distances, in miles, that each car travelled before running out of fuel are given in the table below.
Car12345678
Distance without additive163172195170183185161176
Distance with additive168185187172180189172175
Assuming that the distances travelled follow a normal distribution and stating your hypotheses clearly test, at the \(10 \%\) level of significance, whether or not there is evidence to support the chemist's claim.
(8)