CAIE S1 2009 June — Question 3

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2009
SessionJune
TopicApproximating Binomial to Normal Distribution
TypeCombined binomial and normal events

3 On a certain road \(20 \%\) of the vehicles are trucks, \(16 \%\) are buses and the remainder are cars.
  1. A random sample of 11 vehicles is taken. Find the probability that fewer than 3 are buses.
  2. A random sample of 125 vehicles is now taken. Using a suitable approximation, find the probability that more than 73 are cars.