Edexcel FS1 AS 2021 June — Question 1

Exam BoardEdexcel
ModuleFS1 AS (Further Statistics 1 AS)
Year2021
SessionJune
TopicChi-squared distribution

  1. Flobee sells tomato seeds in packets, each containing 40 seeds. Flobee advertises that only 4\% of its tomato seeds do not germinate.
Amodita is investigating the germination of Flobee's tomato seeds. She plants 125 packets of Flobee's tomato seeds and records the number of seeds that do not germinate in each packet.
Number of seeds that do not germinate0123456 or more
Frequency153538221050
Amodita wants to test whether the binomial distribution \(\mathrm { B } ( 40,0.04 )\) is a suitable model for these data. The table below shows the expected frequencies, to 2 decimal places, using this model.
Number of seeds that do not germinate012345 or more
Expected Frequency24.4240.70\(r\)17.456.73\(s\)
  1. Calculate the value of \(r\) and the value of \(s\)
  2. Stating your hypotheses clearly, carry out the test at the \(5 \%\) level of significance. You should state the number of degrees of freedom, critical value and conclusion clearly. Amodita believes that Flobee should use a more realistic value for the percentage of their tomato seeds that do not germinate.
    She decides to test the data using a new model \(\mathrm { B } ( 40 , p )\)
  3. Showing your working, suggest a more realistic value for \(p\)