Important Topic of Maths - Bar Graphs

The data is represented in the form of pictorial form, It is in the form of vertical or horizontal rectangular bars, They are also known as bar charts. Bar graphs are also known as the data handling in statistics. bars graph is also used in the real-life of business data. let we will discuss what is a bar chart, its properties, uses.

Bar Graph

the data is represented in the form of pictorial form, It is in the form of vertical or horizontal rectangular bars. The bars in the graph can be shown vertically or horizontally. the vertical and horizontal bar is known as x-axis and y-axis. width of each bar is uniform. 

It is one of the ways of data handling Bar graph is an excellent tool to represent data that are independent of one another and that do not need to be in any specific order while being represented. The bars give a visual display for comparing quantities in different categories. The bar graphs have two lines, horizontal and vertical axis, also called the x and y-axis along with the title, labels, and scale range.

Properties of a bar graph

Some of the important properties of a bar graph such as

• The base of all the bars should be common.
• The width of each column in the bar graph should be equal.
• The height of each bar should correspond to the given value.
• The distance between each bar should be common.

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Types of a bar graph

Bar Graphs are mainly classified into two types:

• Vertical Bar Graph:- When the data is represented in vertically form in a graph or chart with the help of rectangular bars that show the measure of data, such graphs are known as vertical bar graphs. On the vertical bar graph should be the y-axis.
• Horizontal Bar Graph:- When the grouped data are represented horizontally in a chart with the help of bars, then such graphs are called horizontal bar graphs, where the bars show the measure of data. The data is depicted here along the x-axis of the graph, and the length of the bars denote the values.

The bars in bar graphs can be plotted horizontally or vertically, but the most commonly used bar graph is the vertical bar graph. Apart from the vertical and horizontal bar graphs, there are two more types of bar graphs, which are given below:

• Grouped Bar Graph:- The grouped bar graph is also called the clustered bar graph, which is used to represent the discrete value for more than one object that shares the same category. In this type of bar chart, the total number of instances are combined into a single bar. In other words, a grouped bar graph is a type of bar graph in which different sets of data items are compared. Here, a single colour is used to represent the specific series across the set. The grouped bar graph can be represented using both vertical and horizontal bar charts.
• Stacked Bar Graph:- The stacked bar graph is also called the composite bar chart, which divides the aggregate into different parts. In this type of bar graph, each part can be represented using different colors, which helps to easily identify the different categories. The stacked bar chart requires specific labelling to show the different parts of the bar. In a stacked bar graph, each bar represents the whole and each segment represents the different parts of the whole.

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Applications of Bar Graphs

Bar graphs are used to match things between different groups or to trace changes over time. Yet, when trying to estimate change over time, bar graphs are most suitable when the changes are bigger.

Bar charts possess a discrete domain of divisions and are normally scaled so that all the data can fit on the graph. When there is no regular order of the divisions being matched, bars on the chart may be organized in any order. Bar charts organized from the highest to the lowest number are called Pareto charts.

Advantages and Disadvantages of Bar Chart

Advantages:

• The bar graph summarises the large set of data in simple visual form.
• It displays each category of data in the frequency distribution.
• It clarifies the trend of data better than the table.
• It helps in estimating the key values at a glance.

Disadvantages:

• Sometimes, the bar graph fails to reveal the patterns, cause, effects, etc.
• It can be easily manipulated to yield fake information.

Difference Between Bar Graph and Histogram

The bar graph and the histogram look similar. But it has an important difference. The major difference between them is that they plot different types of data. In the bar chart, discrete data is plotted, whereas, in the histogram, it plots the continuous data. 

For instance, if we have different categories of data like types of dog breeds, types of TV programs, the bar chart is best as it compares the things among different groups. For example, if we have continuous data like the weight of the people, the best choice is the histogram.

Steps for Draw a Bar Graph

Let us consider an example, we have four different types of pets, such as cat, dog, rabbit, and hamster and the corresponding numbers are 22, 39, 5 and 9 respectively.

In order to visually represent the data using the bar graph, we need to follow the steps given below.

• Step 1: First, decide the title of the bar graph.
• Step 2: Draw the horizontal axis and vertical axis. (For example, Types of Pets)
• Step 3: Now, label the horizontal axis.
• Step 4: Write the names on the horizontal axis, such as Cat, Dog, Rabbit, Hamster.
• Step 5: Now, label the vertical axis. (For example, Number of Pets)
• Step 6: Finally the scale range for the given data.
• Step 7: Finally, draw the bar graph that should represent each category of the pet with their respective numbers.

Example:-In a firm of 400 employees, the percentage of monthly salary saved by each employee is given in the following table. Represent it through a bar graph.

The graph can be represented as: