Activities
Raw Data to Double Graphs
Two categories, one chart — compare boys vs girls, before vs after.
A double bar graph compares two groups side-by-side. Boys vs girls, before vs after, our team vs theirs — same categories, two bars per category.
Edit the data — the chart follows
Building a double bar graph
- Choose your categories (e.g. favourite sport).
- Survey two groups with the same question.
- For each category draw two touching bars, one per group.
- Add a legend and use one shared y-axis scale.
Using different y-axis scales for the two groups is the classic way to lie about which group is bigger. Same scale, always.
Your turn
Group A: 9 chose football. Group B: 6 did. How much taller is A's bar, as a fraction of B's?
Steps
1) Pick categories (e.g. favourite sport: football, tennis, swimming). 2) Survey two groups. 3) For each category, draw two bars touching: one for each group. 4) Add a legend so the reader knows which colour is which.
Use the SAME y-axis scale for both bars. Different scales lie about which group is bigger.