CAIE S1 2016 June — Question 4

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2016
SessionJune
TopicBinomial Distribution
TypeGeneral probability threshold

4 When people visit a certain large shop, on average \(34 \%\) of them do not buy anything, \(53 \%\) spend less than \(
) 50\( and \)13 \%\( spend at least \)\\( 50\).
  1. 15 people visiting the shop are chosen at random. Calculate the probability that at least 14 of them buy something.
  2. \(n\) people visiting the shop are chosen at random. The probability that none of them spends at least \(
    ) 50\( is less than 0.04 . Find the smallest possible value of \)n$.