Skill: Create bar graphs

First, organize the data into categories and their frequencies. A frequency tells how many times each category occurs.

Suppose 15 students were asked about their favorite fruit:

Fruit	Number of students
Apples	6
Bananas	4
Grapes	3
Oranges	2

Step 1: Choose the axes

• Put the categories on one axis.
• Put the number of students on the other axis.
• Label both axes.

For this example, we can make a horizontal bar graph:

• The vertical axis lists the fruits.
• The horizontal axis shows the number of students.

Step 2: Choose an even scale

The greatest frequency is $6$, so use a scale from $0$ to $6$, counting by $1$s:

$$0,\ 1,\ 2,\ 3,\ 4,\ 5,\ 6$$

The spaces between numbers must be equal.

Step 3: Draw one separate bar for each category

Make each bar end at its category’s frequency:

Favorite Fruits

Number of students
       0    1    2    3    4    5    6
       |----|----|----|----|----|----|
Apples ██████████████████████████████  6
Bananas████████████████              4
Grapes █████████████                 3
Oranges████████                    2

Each bar begins at $0$ and reaches the correct number. There is space between categories because fruits are separate categories, not parts of one continuous scale.

Step 4: Check the graph

• Apples has a bar of height or length $6$.
• Bananas has a bar of $4$.
• Grapes has a bar of $3$.
• Oranges has a bar of $2$.

The graph shows that apples were the most popular fruit and oranges were the least popular fruit.