# Bar Graph vs. Line Graph

A bar graph and a line graph are two different ways of representing categorical data in statistics.

## When to Use Bar Graph and Line Graph

### Bar Graph

A bar graph uses rectangular blocks of different heights, where the height represents the value of the quantity. The quantity can be anything from frequencies, percentages, or values in any unit of measurement.

However, they are mainly used to represent data divided into categories. It is a good choice for comparing data between classes when the values differ significantly. An insignificant or slight difference in values will not be evident.

For example, if we represent the data on the number of students that preferred mathematics as their most liked subject from grade 8 to grade 12 in the table below, we will obtain the following bar graph.

### Line Graph

In contrast, a line graph represents data that changes over time. It is a continuous line that connects individual data points in a curve. Compared to the bar graph, a line graph is a better choice to visualize the relationship between two variables over time or space. They can also track changes over the same period for multiple groups.

For example, if we want to monitor the number of visitors in a shop each month for 6 months, we can get an idea about it if we plot a line graph with the given data.

## Differences

Thus, the main differences between a bar and a line graph are: