Two delivery companies record delivery times.
median (min)IQR (min)sample sizeA31820B291480\begin{array}{c|ccc}&\text{median (min)}&\text{IQR (min)}&\text{sample size}\\\hline A&31&8&20\\B&29&14&80\end{array}ABmedian (min)3129IQR (min)814sample size2080
Compare the delivery times of the two companies.
Give one reason why the summaries do not establish that B provides the better service.
121 exam-style questions on OCR (MEI) A Level Maths 2.2 Data Presentation and Interpretation, covering 2.2.1 Types of data and standard diagrams, 2.2.2 Area in a histogram is proportional to frequency, 2.2.3 Cumulative frequency diagram, 2.2.4 Describe frequency distributions, 2.2.5 Samples and theoretical distributions, 2.2.6 Interpret a scatter diagram, 2.2.7 Distinct sections and outliers in scatter diagrams, 2.2.8 Correlation and causation, 2.2.9 Select or critique data presentation techniques, 2.2.10 Measures of central tendency, 2.2.11 Simple measures of spread, 2.2.12 Variance and standard deviation, 2.2.13 Outliers, 2.2.14 Cleaning data, and 2.2 Data Presentation and Interpretation. Each one has a worked solution and a mark scheme showing where the marks go.