OCR S2 2006 June — Question 5

Exam BoardOCR
ModuleS2 (Statistics 2)
Year2006
SessionJune
TopicApproximating Binomial to Normal Distribution
TypeOverbooking probability problems

5 An airline has 300 seats available on a flight to Australia. It is known from experience that on average only \(99 \%\) of those who have booked seats actually arrive to take the flight, the remaining \(1 \%\) being called 'no-shows'. The airline therefore sells more than 300 seats. If more than 300 passengers then arrive, the flight is over-booked. Assume that the number of no-show passengers can be modelled by a binomial distribution.
  1. If the airline sells 303 seats, state a suitable distribution for the number of no-show passengers, and state a suitable approximation to this distribution, giving the values of any parameters. Using the distribution and approximation in part (i),
  2. show that the probability that the flight is over-booked is 0.4165 , correct to 4 decimal places,
  3. find the largest number of seats that can be sold for the probability that the flight is over-booked to be less than 0.2.