CAIE S1 2020 November — Question 5

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

5 The time in hours that Davin plays on his games machine each day is normally distributed with mean 3.5 and standard deviation 0.9.
  1. Find the probability that on a randomly chosen day Davin plays on his games machine for more than 4.2 hours.
  2. On 90\% of days Davin plays on his games machine for more than \(t\) hours. Find the value of \(t\).
  3. Calculate an estimate for the number of days in a year ( 365 days) on which Davin plays on his games machine for between 2.8 and 4.2 hours.