For this last activity in Lesson 25, we will take a look at two different types of graphs: bar graphs and line graphs.

A bar graph (sometimes called bar chart) is a graphical display of data using bars of different heights. As you can see from the bar graph to the right, the higher the bar (hours of television watched), the higher the number of students. So, for example, the bar chart tells us that the number of students who watch the most hours of television were those between the ages of 9 to 11, and the number of students who watch the least hours of television were those between the ages of 0 to 2 and 15 to 17.

Let's take a look at the example again from the last activity.

Imagine you just did a survey of your friends to find which kind of movie they liked best. The results are displayed below in a table.

You can also display this information in a bar graph.

Using bar graphs is a really good way to show relative sizes: we can see which types of movie are most liked and which are least liked, at a glance. In the bar graph above, it is easy to see that the favourite type of movie is romance, and the least favourite type of movie is drama.

Bar graphs can be shown in two different ways.

They can be vertical (up and down).

Graphs can also be horizontal (side to side).

Now let's practise reading a bar graph. Look at the bar graph below, and then answer the questions that follow.

Now let's take a look at line graphs. A line graph is a graph that shows information that is connected in some way (such as change over time). From the line graph on the left, we can see that the age in years of small town teens with cellphones is lowest at the age of 13 (at 229) and the highest at the age of 19 (at 642.)

Let's look at an example!

You are learning facts about dogs, and each day you do a short test to see how good you are. These are the results:

We can display this information in a line graph.

The line graph shows the change over time on how many facts you got correct. On day 1, you got 3 facts correct, but on day 4 you got 15 facts correct!

Now let's practise reading a line graph. Look at the line graph below, and then answer the questions that follow.

The graph below shows the number of fish caught in a day.

  Self-check!

Digging Deeper!

Click on the Play button below to watch a video on how to read simple bar graphs.

Click on the Play button below to watch a video on line graphs.