A Bar Graph or Bar Chart represents the categorial data in the form of a rectangular bars to make user understand the stats in a simpler way. Bar Graph is an important aspect of Data Interpretation and is asked in various competitive exams. The bar graph can be classified into six categories. This classification is based on their structure and how many parameters they can represent for a single category. In this maths article, we will describe all these six types along with examples.

Before getting into the different types, let us first go through a brief introduction of what are bar graphs.

What are Bar Graphs?

Bar Graphs are a graphical representation of data based on statistics and numerical figures. A bar graph uses the two axes – x-axis and y-axis to plot rectangular bars. One of the axes represents the observation/category which is usually a fixed variable, while the other axis represents the numerical magnitude that the observation carries. The bars run up to the point of value that is proportional to the value of the observation it represents.
Learn about Simple Bar Graph here.

Types of Bar Graph

Bar graphs are majorly used to compare various observations based on a certain parameter(s). Based on the structure of the bars and the number of parameters, the bar graph is classified into the following six types.

• Horizontal bar graph
• Vertical bar graph
• Double bar graph (Grouped bar graph)
• Multiple bar graph (Grouped bar graph)
• Stacked bar graph
• Bar line graph

Let us now discuss these in detail.

Horizontal Bar Graph

When the Y-axis represents the observation to be compared, and the x-axis represents the magnitude of the observations, then the bars run horizontally along the x-axis up to the point of value proportional to the observation. Such a bar graph is known as a horizontal bar graph.

Example- In the horizontal bar graph given below the percentage of four students is shown.

Vertical Bar Graph

Vertical bar graphs are just the opposite of horizontal bar graphs. Vertical bar graphs are preferred more than horizontal bar graphs.

Here, the x-axis represents the observation/category which is usually a fixed variable. The y-axis represents the numerical values that the observation carries. The bars start from the x-axis and run vertically along the y-axis up to the point of value proportional to that particular observation.

Example- if we take the same example as above, the vertical bar graph will look something like the following:

Also know about Bar Line Graph here.

Grouped Bar Graph 

Both the above types discussed until now were simple bar graphs that were plotted on the basis of only one parameter. In the above two examples, the student is the observation that is being compared, while the percentage is the parameter that is the basis of comparison.

A grouped bar graph gives you the advantage to compare various observations on the basis of more than one parameter. Based on the number of parameters used, grouped bar graphs can be further classified into two types.

• Double bar graph
• Multiple bar graph

Double Bar Graph

In a double bar graph, as the name suggests, you can make a comparison among various observations or categories using two parameters. However, those two parameters should be measured in similar quantities, which means that they should be of the same unit.

In a double bar graph, two bars are drawn for each observation. You must plot the two bars with two different and contrasting colors to emphasize the difference. You must also mention on the graph what each color represents.

Example- the following double bar graph shows the sales percentage and profit percentage of five stores

Multiple Bar Graph

Again, as the name suggests, in a multiple bar graph, you can make a comparison among various observations on the basis of multiple parameters. You can include as many parameters as you wish, however, each parameter should have the same unit of measurement.

In a multiple bar graph, there are as many bars for each observation as there are parameters. For instance, if the marks of six students are being compared in four subjects, then for each student there will be four bars drawn.

Example- The following multiple bar graph shows the marks in 4 subjects of six students.

Learn about Multiple Bar Diagram

Stacked Bar Graph

A stacked bar graph also represents various parameters in a single graph. The difference is that in a stacked bar graph all the parameters are represented in a single bar. So you can say that there are segments of a total in a single bar.

A stacked bar graph has the ability to convey a lot of information all together in a compact and precise format. However, stacked bar graphs are rarely used because they can be confusing at times while representing too much information.

Example- The following stacked bar graph shows the number of red candies, blue candies, green candies, and yellow candies sold by four teams in a fete.

Bar Line Graph

A bar line graph is a combination of a bar graph and a line graph. It is a type of grouped bar graph. In this type of bar graph also you can compare observations on the basis of more than one parameter. The difference is that you can take the parameters of different units in this type.

For example, in this case, if you want to compare the students on the basis of their marks in one subject and their total percentage, you can do so. For this, you have to draw two y-axes. One y-axis will represent one parameter and the other will represent the second parameter. The bars will be plotted according to one y-axis and the line will be plotted according to the other y-axis.

Example- the following bar line graph shows the percentage and marks in Science of 4 students of a class.

How to draw a Bar Graph

The following steps can be used to draw a bar graph:

Step 1: Determine the Data Categories: Identify the categories or variables that you want to represent on the bar graph. These can be anything from product names, survey response options, time periods, or any other distinct groups you wish to compare.

Step 2: Label the Axes: Draw two perpendicular lines to create the x-axis (horizontal) and y-axis (vertical) on your graph paper or digital drawing tool. Label the x-axis with the categories or variables you identified in Step 1, and label the y-axis with the numerical values or measurements that will be represented by the bar heights or lengths.

Step 3: Determine the Scale: Decide on the scale for each axis, based on the range of values you want to represent. Ensure that the scale allows for clear differentiation between the values and provides sufficient space for the bars. For example, if you are representing quantities, determine an appropriate unit of measurement and spacing on the y-axis.

Step 4: Draw the Bars: For each category or variable, draw a rectangle or vertical bar above its corresponding label on the x-axis. The height or length of the bar should be proportional to the value or quantity it represents. Use a ruler or straight edge to ensure straight and uniform bars.

Step 5: Add Colour or Patterns: To enhance visual distinction between the bars, you can assign different colours or patterns to each category or variable. Use a consistent and meaningful colour scheme or pattern scheme that makes it easy to identify and differentiate the bars.

Step 6: Label the Bars and Axes: Add labels to the bars if necessary, especially if the numerical values or measurements are not explicitly shown on the graph. Ensure that the labels are clear, legible, and aligned appropriately with their respective bars. Don't forget to include a title for the graph and label the x-axis and y-axis with appropriate descriptions.

Step 7: Include a Legend (if needed): If you have used colours or patterns to represent different categories or variables, consider including a legend that explains the colour or pattern used for each category.

Step 8: Review and Refine: Take a step back and review your bar graph. Check for any errors, ensure that the bars accurately represent the data, and verify that the graph clearly conveys the intended information. Make any necessary refinements or adjustments to improve the clarity and aesthetics of the graph.

Properties of Bar Graph

Here are the key properties of a bar graph:

Vertical or Horizontal Bars: A bar graph can have vertical or horizontal bars. In a vertical bar graph, the bars are plotted vertically along the y-axis, while in a horizontal bar graph, the bars are plotted horizontally along the x-axis.

Bar Length or Height: The length or height of each bar represents a specific value or quantity associated with the corresponding category or variable being represented. The length or height of the bar is proportional to the magnitude of the data it represents.

Equal Width: In a bar graph, the width of each bar is usually the same. This ensures that the visual comparison of bar lengths accurately reflects the differences in data values.

Categorical Data: Bar graphs are particularly useful for representing categorical data, where each bar represents a different category or variable. The categories are typically displayed along the x-axis (for vertical bar graphs) or the y-axis (for horizontal bar graphs).

Gaps Between Bars: There is usually a small gap between adjacent bars in a bar graph. This gap helps to visually distinguish between individual bars and prevents them from merging into a continuous line.

Labels and Scales: Bar graphs include labels for the categories along the x-axis (or y-axis for horizontal bar graphs) and labels for the numerical values along the y-axis (or x-axis for horizontal bar graphs). The scales on the axes provide a reference for interpreting the values represented by the bar heights or lengths.

Colour or Patterns: Bar graphs often use different colours or patterns to differentiate between bars belonging to different categories or variables. This enhances the visual distinction and makes it easier to identify and compare the data.

Title and Captions: A bar graph typically includes a title that describes the purpose or subject of the graph. Captions or legends may also be used to provide additional information about the data being presented.

Applications of Bar Graphs

Bar graphs have various applications across different fields due to their simplicity and effectiveness in presenting categorical data. Here are some common applications of bar graphs:

Data Comparison: Bar graphs are widely used to compare data across different categories or variables. They allow for easy visual comparison of values, making it convenient to identify patterns, trends, and differences in data sets. Bar graphs are commonly used in market research, sales analysis, and performance evaluation.

Survey Results: Bar graphs are useful for presenting survey results or opinion polls. Each bar represents a response option or category, and the height or length of the bar reflects the frequency or percentage of respondents choosing that option. Bar graphs make it easy to understand and compare the distribution of responses.

Population Statistics: Bar graphs are often employed to display population statistics, such as demographic data, age distribution, or educational attainment. Each bar represents a specific category, such as age groups or education levels, allowing for a visual representation of the population distribution.

Financial Analysis: Bar graphs are valuable in financial analysis to represent financial data, such as revenue, expenses, or profit across different time periods or business units. They provide a clear visual representation of financial performance, making it easier to identify trends and make informed decisions.

Inventory Management: Bar graphs can be used in inventory management to track and compare the levels of different products or inventory items. Each bar represents a product or item, and the length of the bar indicates its quantity or stock level. Bar graphs help in identifying low or high stock levels and managing inventory effectively.

Academic Performance: Bar graphs are often employed to display academic performance data, such as grades or test scores of students. They allow for easy comparison of performance across different subjects or students, aiding in identifying areas of improvement or strengths.

Sports Statistics: Bar graphs find applications in sports statistics, where they are used to represent data such as goals scored, assists, or player performance. Each bar represents a player or team, and the length of the bar reflects the corresponding statistic, facilitating comparisons and analysis.

Difference between Bar Graph and Histogram

We hope that you understood the different types of bar graphs, the difference between them, and how to draw them through this article. If you have any other doubts or suggestions for us then you can contact us on the details given at the end of this page. If you wish to access more such learning material then you can download the Testbook App. With Testbook you can prepare for any government exam from the comfort of your house. On our app, you can get video tutorials, live interactive classes, mock tests, and other such perks. So hurry up and download the app from the play store NOW!