CAIE Further Paper 4 2021 June — Question 5

Exam BoardCAIE
ModuleFurther Paper 4 (Further Paper 4)
Year2021
SessionJune
TopicPoisson Distribution
TypeMean-variance comparison for Poisson validation

5 Chai packs china mugs into cardboard boxes. Chai's manager suspects that breakages occur at random times and that the number of breakages may follow a Poisson distribution. He takes a small sample of observations and finds that the number of breakages in a one-hour period has a mean of 2.4 and a standard deviation of 1.5.
  1. Explain how this information tends to support the manager's suspicion.
    The manager now takes a larger sample and claims that the numbers of breakages in a one-hour period follow a Poisson distribution. The numbers of breakages in a random sample of 180 one-hour periods are summarised in the following table.
    Number of breakages01234567 or more
    Frequency213346312316100
    The mean number of breakages calculated from this sample is 2.5.
  2. Use the data from this larger sample to carry out a goodness of fit test, at the \(10 \%\) significance level, to test the claim.