CAIE S1 2017 November — Question 7

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2017
SessionNovember
TopicNormal Distribution
TypeIndependent events across days/trials

7 Josie aims to catch a bus which departs at a fixed time every day. Josie arrives at the bus stop \(T\) minutes before the bus departs, where \(T \sim \mathrm {~N} \left( 5.3,2.1 ^ { 2 } \right)\).
  1. Find the probability that Josie has to wait longer than 6 minutes at the bus stop.
    On \(5 \%\) of days Josie has to wait longer than \(x\) minutes at the bus stop.
  2. Find the value of \(x\).
  3. Find the probability that Josie waits longer than \(x\) minutes on fewer than 3 days in 10 days.
  4. Find the probability that Josie misses the bus.