Chapter 4: Data Handling and Presentation

We live in an age drowning in data. Every cricket match, weather report, election result, and shopping bill is a small heap of data. Mathematics offers tools to gather data, organise it, and present it so that other people can read it at a glance.

This chapter takes you through the full journey. We start by collecting data , going out and asking, observing, or measuring. We then organise it using tables and tally marks so that messy lists become tidy counts. Finally we present the data using pictographs (rows of small symbols), bar graphs (rectangles whose lengths show counts), and other visual tools. Picking the right tool for the right data is itself a useful skill.

Along the way we will practise interpreting data we did not collect ourselves. Looking at a graph in a newspaper and asking sensible questions , Is this comparing the right things? Could the picture be misleading? , is a part of mathematics that affects how we read the world.

What's inside

1. Collecting and organising data , from raw lists to tally tables.
2. Pictographs , telling a story with little pictures.
3. Bar graphs , using lengths to compare.
4. Interpreting graphs , asking the right questions about a chart.

Key results / Formula card

Total of all frequencies in a table = total number of observations.

In a pictograph, if one picture stands for $n$ items, then $k$ pictures show $k \times n$ items.

How to read this chapter

Read with a real example beside you. Survey your family about anything , favourite films, daily glasses of water, hours of sleep , and turn that data into the kind of charts described here. Data handling becomes alive only when your own data is involved.