CAIE S1 2020 November — Question 3

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2020
SessionNovember
TopicNormal Distribution
TypeMixed calculations with boundaries

3 Pia runs 2 km every day and her times in minutes are normally distributed with mean 10.1 and standard deviation 1.3.
  1. Find the probability that on a randomly chosen day Pia takes longer than 11.3 minutes to run 2 km .
  2. On \(75 \%\) of days, Pia takes longer than \(t\) minutes to run 2 km . Find the value of \(t\).
  3. On how many days in a period of 90 days would you expect Pia to take between 8.9 and 11.3 minutes to run 2 km ?