Introduction to Bar Graphs
Rohan wanted to arrange the birthdays of his classmates according to their months. He then wants to display the data in a way that he can visually understand them. This is where he faces a problem. He doesn't want to use a pictograph since it takes too much time also might be difficult. He want to do it in an easier method. This is where bar graph comes in.
What are Bar Graphs?
 A bar graph is a specific way of representing data using rectangular bars where the length of each bar is proportional to the value they represent.
 Bar graphs are an excellent tool when representing data that are independent of one another and don’t need to be in any specific order while being represented.
 In the image below, the data is divided according to its color(category).
Now, let us come back to the case of Rohan. He can now display his data in the form of a bar graph.
From the above graph, we can easily say that the maximum number of birthdays is in the month of June just by looking. This is the advantage of bar graphs.
Note: If the frequency of data is very large, then bar graphs are always advisable since pictographs become time consuming and very difficult to make.
Properties of a Bar Graph
 All bars must be of equal width.
 The bars can be drawn horizontally as well as vertically as per our needs.
 There must be equal spacing between the bars.
 The height of the bar is proportional to the data they represent.
 All bars must share a common base.
How to draw a Bar Graph?
The following steps must be followed while drawing a bar graph:
 First, draw a horizontal and a vertical line( i.e. the xaxis and yaxis ).
 Sort the data collected according to the category.
 Choose a scale. Scale represents how much of the data is represented by a unit length of the bar.
 Now, draw the bar with heights corresponding to the value of the data.
Now, we want to represent a large amount of data. This will be difficult as we have only a limited area to draw on. This is where scaled bar graphs come in.
 Scaled bar graphs are used to represent large sums of data.
 The data is scaled down to fit numbers that are easier to work with.
 This involves the same scaling factor to every entry in a particular graph, that is simply multiplied to the result to get the final number.
Test yourself by trying out the simulation given below. If you finish one set you can reset it to get a different question set.
Author: John Ulbright
Activity
Activity Name  Sub_BarGraph_Activity 
Item Name 1  Sub_BarGraph_Item1 
Item Name 2  Sub_BarGraph_Item2 
Item Name 3  Sub_BarGraph_Item3 
Item Name 4  Sub_BarGraph_Item4 
Item Name 5  Sub_BarGraph_Item5 
Why are Bar Graphs important?
The importance of bar graphs come out when we want to compare data sets that are independent from one another. For example, sales report graphs for different quarters or years.
They help in analysing patterns over long periods of time and lend great value to predictive studies.
Bar graphs, when combined with double and triple charts, are also of benefit in statistical studies as they provide learners with a more defined picture of the dataset by just using simple rectangular bars.
Frequently Asked Questions
1.What are bar graphs used for?
Ans. Bar graphs are used to compare things category wise.
2.What is a bar graph?
Ans. A bar graph is a specific way of representing data using rectangular bars where the length of each bar is proportional to the value they represent.
3.How do I make a bar graph?
Ans.
 First, draw a horizontal and a vertical line( i.e. the xaxis and yaxis ).
 Sort the data collected according to the category.
 Choose a scale. Scale represents how much of the data is represented by a unit length of the bar.
 Now, draw the bar with heights corresponding to the value of the data
4.What are the types of bar graphs?
Ans. Mainly there are 3 types of bar graphs:

Horizontal bar graph

Vertical bar graph

Line graphs
5.What is a double bar graph?
Ans. A double bar graph is just like a normal bar graph. The only difference is that it compares 2 data groups.