Edexcel S3 2018 Specimen — Question 3

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2018
SessionSpecimen
TopicHypothesis test of a Poisson distribution

3. The number of accidents on a particular stretch of motorway was recorded each day for 200 consecutive days. The results are summarised in the following table.
Number of accidents012345
Frequency4757463596
  1. Show that the mean number of accidents per day for these data is 1.6 A motorway supervisor believes that the number of accidents per day on this stretch of motorway can be modelled by a Poisson distribution. She uses the mean found in part (a) to calculate the expected frequencies for this model. Her results are given in the following table.
    Number of accidents012345 or more
    Frequency40.3864.61\(r\)27.5711.03\(s\)
  2. Find the value of \(r\) and the value of \(s\), giving your answers to 2 decimal places.
  3. Stating your hypotheses clearly, use a \(10 \%\) level of significance to test the motorway supervisor's belief. Show your working clearly.