Edexcel S1 2016 January — Question 2

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2016
SessionJanuary
TopicData representation
TypeEstimate single values from cumulative frequency graph

2. \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{70137e9a-0a6b-48b5-8dd4-c436cb063351-04_284_1244_260_388} \captionsetup{labelformat=empty} \caption{Figure 1}
\end{figure} Figure 1 shows part of a box and whisker plot for the marks in an examination with a large number of candidates. Part of the lower whisker has been torn off.
  1. Given that \(75 \%\) of the candidates passed the examination, state the lowest mark for the award of a pass.
  2. Given that the top \(25 \%\) of the candidates achieved a merit grade, state the lowest mark for the award of a merit grade. An outlier is defined as any value greater than \(c\) or any value less than \(d\) where $$\begin{aligned} & c = Q _ { 3 } + 1.5 \left( Q _ { 3 } - Q _ { 1 } \right)
    & d = Q _ { 1 } - 1.5 \left( Q _ { 3 } - Q _ { 1 } \right) \end{aligned}$$
  3. Find the value of \(c\) and the value of \(d\).
  4. Write down the 3 highest marks scored in the examination. The 3 lowest marks in the examination were 5, 10 and 15
  5. On the diagram on page 7, complete the box and whisker plot. Three candidates are selected at random from those who took this examination.
  6. Find the probability that all 3 of these candidates passed the examination but only 2 achieved a merit grade.
    \includegraphics[max width=\textwidth, alt={}, center]{70137e9a-0a6b-48b5-8dd4-c436cb063351-05_285_1628_2343_166} Turn over for a spare diagram if you need to redraw your plot.