Bar Graph - Cycle 2

| Mathematics

What Is a Bar Graph?

Definition

A bar graph presents the results of a survey using bars.

For example:

Example of a bar graph.

What Are the Parts of a Bar Graph?

A bar graph always has a title that presents the subject of a survey.

Example

The title indicates that this bar graph represents the number of spinning tops in each colour at a daycare.

Example of a bar graph title.

A bar graph has 2 axes: a horizontal axis and a vertical axis. Each axis must have a label to indicate what it represents.

Example

In this graph, the horizontal axis represents the colour of the spinning tops. The vertical axis represents the number of spinning tops.

Example of axis labels in a bar graph.

The scale on the vertical axis has equal intervals.

Example

The interval between the numbers on the vertical axis is +2.

Example of intervals on a bar graph.

In a bar graph, the data (results) are represented using bars. The number associated with the height of each bar indicates the amount of data in each category.

Examples

The height of the blue bar is aligned with the number 4 on the vertical axis. So, there are 4 blue spinning tops.

The height of the yellow bar is aligned with the number 8 on the vertical axis. So, there are 8 yellow spinning tops.

Example of the number associated with the height of a bar.

How Do We Interpret a Bar Graph?

To interpret a bar graph, analyze each part of the graph while keeping in mind the question asked.

Example

How many students prefer mozzarella cheese?

Example of the interpretation of a bar graph.

  1. I locate the bar that represents mozzarella.

    The mozzarella category is represented by the orange bar.

Example of the interpretation of a bar graph.
  1. I observe the height of the orange bar and the number associated with it.

    The height of the orange bar is halfway between 8 and 10. Since the bar is halfway between 8 and 10, there are 9 students.

Example of the interpretation of a bar graph.

9 students prefer mozzarella cheese.

Example

How many students are there in this 3rd grade class?

Example of the interpretation of a bar graph.

  1. I observe the height of each bar and the number associated with it.

    The number associated with the height of the blue bar indicates that 4 people prefer brie.

    The number associated with the height of the pink bar indicates that 12 people prefer cheddar.

    The height of the orange bar is between 8 and 10 students. Since the bar is halfway between 8 and 10, the number of students is 9. So, 9 students prefer mozzarella.

    The number associated with the height of the green bar indicates that 2 people prefer parmesan.

Example of the interpretation of a bar graph.
  1. Add the amount of students in each category.
4 + 12 + 9 + 2 = 27

There are 27 students in this class.