Bar chart

A bar chart is a chart with bars of different heights. Taller bar = bigger count.

This chart is the best one for comparing — at a glance you see what is biggest and what is smallest.

Parts of a bar chart

• Horizontal axis (bottom) — categories (what we compare).
• Vertical axis (left) — numbers (the count).
• Bars — bar height = the count.

Example: favourite desserts

In class we asked about favourite dessert:

The chart has three bars:

• The "ice cream" bar reaches up to 4.
• The "juice" bar reaches up to 7.
• The "cake" bar reaches up to 5.

How to read a bar chart

1. Pick a category (e.g. "juice").
2. Look at the bar height.
3. Read the number on the vertical axis.

For "juice" the bar reaches 7, so 7 children.

Questions we answer

From the chart we read:

• "How many were X?" → pick the bar, look at the height.
• "Which had the most?" → the tallest bar.
• "Which had the fewest?" → the shortest bar.
• "How many more X than Y?" → subtract bar heights.
• "How many altogether?" → add all the heights.

Example: compare

In the chart above:

• Most: juice (7).
• Fewest: ice cream (4).
• Juice − ice cream: 7 − 4 = 3 more children chose juice.
• Altogether: 4 + 7 + 5 = 16 children answered.

Summary

• Bar chart = bars of different heights.
• Taller bar = bigger count.
• Bottom axis = categories, left axis = numbers.
• Best for comparing and for differences.