Edexcel S1 2011 January — Question 3

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2011
SessionJanuary
TopicData representation
TypeOutliers from box plot or summary statistics

3. Over a long period of time a small company recorded the amount it received in sales per month. The results are summarised below.
Amount received in sales (£1000s)
Two lowest values3,4
Lower quartile7
Median12
Upper quartile14
Two highest values20,25
An outlier is an observation that falls
either \(1.5 \times\) interquartile range above the upper quartile or \(1.5 \times\) interquartile range below the lower quartile.
  1. On the graph paper below, draw a box plot to represent these data, indicating clearly any outliers.
    (5)
    \includegraphics[max width=\textwidth, alt={}, center]{c78ec7b6-dd06-4de1-94c2-052a5577dd10-05_933_1226_1283_367}
  2. State the skewness of the distribution of the amount of sales received. Justify your answer.
  3. The company claims that for \(75 \%\) of the months, the amount received per month is greater than \(\pounds 10000\). Comment on this claim, giving a reason for your answer.
    (2)