Edexcel S3 2011 June — Question 5

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2011
SessionJune
TopicChi-squared distribution

  1. The number of hurricanes per year in a particular region was recorded over 80 years. The results are summarised in Table 1 below.
\begin{table}[h]
No of
hurricanes,
\(h\)
01234567
Frequency0251720121212
\captionsetup{labelformat=empty} \caption{Table 1}
\end{table}
  1. Write down two assumptions that will support modelling the number of hurricanes per year by a Poisson distribution.
  2. Show that the mean number of hurricanes per year from Table 1 is 4.4875
  3. Use the answer in part (b) to calculate the expected frequencies \(r\) and \(s\) given in Table 2 below to 2 decimal places. \begin{table}[h]
    \(h\)01234567 or more
    Expected
    frequency
    0.904.04\(r\)13.55\(s\)13.6510.2113.39
    \captionsetup{labelformat=empty} \caption{Table 2}
    \end{table}
  4. Test, at the \(5 \%\) level of significance, whether or not the data can be modelled by a Poisson distribution. State your hypotheses clearly.