Presenting data with charts and graphs
Computer Science · Key Stage 2 · The School
From numbers to a picture
A chart turns a table of numbers into a picture. A reader can take it in at a glance. The right chart depends on the data. A bar chart suits separate groups. A line graph suits change over time. Picking the wrong chart can hide the very thing the data was meant to show. A well-chosen chart makes its point before a single word is read.
Choosing the right chart
Favourite fruit results fit a bar chart well. Each fruit is its own separate group. A bar chart makes them easy to compare. Temperature checked every hour fits a line graph instead. It is one thing changing over time, not separate groups. Ask what the data actually is before choosing how to draw it. Getting this one decision right makes everything that follows easier.
How a chart can mislead
A bar chart usually starts at zero at the bottom. Start it higher instead, and small gaps look huge. Two bars that are close in value can suddenly look very different. Always check where a chart starts before trusting what it shows you at a glance. The numbers can be entirely true and the picture still misleading.
Turning a tally into a chart
A fruit tally showed: apple six, banana four, orange three, other two. Drawn as a bar chart, four bars now show those exact heights. A reader sees at once that apple won. The tally marks alone made that harder to see quickly. The numbers did not change at all — only how easy they were to read did.