Edexcel S2 2016 June — Question 4

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2016
SessionJune
TopicContinuous Uniform Random Variables
TypeWaiting time applications

  1. The waiting times, in minutes, between flight take-offs at an airport are modelled by the continuous random variable \(X\) with probability density function
$$f ( x ) = \begin{cases} \frac { 1 } { 5 } & 2 \leqslant x \leqslant 7
0 & \text { otherwise } \end{cases}$$
  1. Write down the name of this distribution. A randomly selected flight takes off at 9am
  2. Find the probability that the next flight takes off before 9.05 am
  3. Find the probability that at least 1 of the next 5 flights has a waiting time of more than 6 minutes.
  4. Find the cumulative distribution function of \(X\), for all \(x\)
  5. Sketch the cumulative distribution function of \(X\) for \(2 \leqslant x \leqslant 7\) On foggy days, an extra 2 minutes is added to each waiting time.
  6. Find the mean and variance of the waiting times between flight take-offs on foggy days.