Edexcel S3 2017 June — Question 2

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2017
SessionJune
TopicChi-squared distribution

2. A school uses online report cards to promote both hard work and good behaviour of its pupils. Each card details a pupil's recent achievement and contains exactly one of three inspirational messages \(A , B\) or \(C\), chosen by the pupil's teacher. The headteacher believes that there is an association between the pupil's gender and the inspirational message chosen. He takes a random sample of 225 pupils and examines the card for each pupil. His results are shown in Table 1. \begin{table}[h]
\cline { 2 - 5 } \multicolumn{2}{c|}{}Inspirational message\multirow{2}{*}{Total}
\cline { 3 - 5 } \multicolumn{2}{c|}{}\(\boldsymbol { A }\)\(\boldsymbol { B }\)\(\boldsymbol { C }\)
\multirow{2}{*}{
Pupil's
gender
}
Male253745107
\cline { 2 - 6 }Female325036118
Total578781225
\captionsetup{labelformat=empty} \caption{Table 1}
\end{table} Stating your hypotheses clearly, test, at the \(10 \%\) level of significance, whether or not there is evidence to support the headteacher's belief. Show your working clearly. You should state your expected frequencies correct to 2 decimal places.