CAIE S1 2021 November — Question 6

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2021
SessionNovember
TopicNormal Distribution
TypeMultiple probability calculations

6 The times taken, in minutes, to complete a particular task by employees at a large company are normally distributed with mean 32.2 and standard deviation 9.6.
  1. Find the probability that a randomly chosen employee takes more than 28.6 minutes to complete the task.
  2. \(20 \%\) of employees take longer than \(t\) minutes to complete the task. Find the value of \(t\).
  3. Find the probability that the time taken to complete the task by a randomly chosen employee differs from the mean by less than 15.0 minutes.