80 students completed a logic puzzle. Their completion times, in minutes, are summarised by a box plot with minimum 2.0, lower quartile 4.5, median 5.5, upper quartile 7.0 and maximum 14.5. The value 14.5 is shown as a high outlier on the box plot.
∑x=480∑x2=3060 \sum x = 480 \quad \sum x^2 = 3060 ∑x=480∑x2=3060Write down the range of the times.
Write down the interquartile range of the times.
Calculate the mean and the standard deviation of the times.
State, giving a reason, whether you would recommend using the mean and standard deviation or the median and interquartile range to describe these data.
28 exam-style questions on Edexcel AS Level Maths Representations of Data, covering 3.1 Outliers, 3.2 Box Plots, 3.3 Cumulative Frequency, 3.4 Histograms, and 3.5 Comparing Data. Each one has a worked solution and a mark scheme showing where the marks go.