This tutorial explains the essential differences between Bar Chart Vs Histogram for representation of data along with the advantages and usage:
When we hear the word Bar Chart or Histogram, one thing that comes to the minds of most of us would be a pictorial representation of data. This is absolutely true, but for explaining the differences between the two, we may not be so clear about the differences.
In this article, we will understand what a Bar Chart and Histogram are and when to use a Histogram vs Bar Graph. Further, we will see what benefits each of these charts offers. We shall also look at the drawbacks of the Bar Chart and Histogram.
To get a clear and quick understanding of the differences between the two, a comparison chart – Bar chart vs Histogram has also been included. At last, we have a few FAQs related to this topic where you could find quick answers to the doubts you might have about this topic.
Table of Contents:
Bar Chart Vs Histogram – Key Differences
What Is A Bar Chart
A Bar Chart is often also referred to as a Bar Graph. As goes the name, it uses horizontal or vertical bars to represent data. These bars of varying sizes represent the values of varying categories.
The Bar Chart has two axes, one that represents different categories and the other that represents the corresponding values. A bar is then constructed for each category to represent its value.
Let us understand this by drawing a simple Bar Chart. Below is a Bar Chart showing the no. of people traveling to a particular tourist location in various months. The months considered are Jan, Feb, Mar, April, May, and June.
BAR CHART:
Where is it used?
A Bar chart can represent categorical data. It is used to compare the values of different categories. The categories are placed on one axis and the other axis has the corresponding value. This chart thus enables one to view and compare the data at a glance.
Below are some examples that will give you an idea of where a Bar chart can be used:
- To compare the number of trees of different varieties in a farmhouse.
- To compare the temperatures of each month in a year.
- To compare the number of visitors, month-wise in a tourist location.
- To compare the animals that people prefer to keep as pets.
- To compare the most favorite fruits of children.
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What Is A Histogram
A Histogram is a pictorial representation depicting the frequency of data falling in various data ranges.
In a histogram, first, divide the entire range of values into a series of intervals that are consecutive and do not overlap. These intervals may or may not be of the same size but should be adjacent. Then the number of data values (frequencies) falling in each range is determined.
The histogram has two axes, one representing the range of values and the other representing the frequency of the range. Rectangles are drawn over the interval range to represent the number of data values that lie within that range.
It is to be noted that there is no gap between the value range defined and the rectangles are drawn to touch each other.
Let us understand this by drawing a histogram with the below data, which shows the height of 15 students.
To construct the Histogram, we need the data range and its frequencies.
So, the height is first divided into fixed intervals that do not overlap. Let us consider an interval of 110-119, 120-129, 130-139, 140-149. Count the number of children falling in each of these height intervals. Using the interval range and the count, construct the below Histogram.
HISTOGRAM:
Where is it used?
As already mentioned above, a Histogram is used for determining the frequencies of continuous data. As the data is represented as intervals, it can therefore be used in all those places where we wish to know the count of a data interval.
Below are some examples that will give you an idea of where a Histogram can be used:
- The number of complaints received at a customer care center between 9 AM to 9 PM.
- The count of different height ranges of trees in an area.
- The number of waiting customers in a queue during different time intervals.
- The number of flights arriving at a terminal during different time intervals.
Benefits Of Using Bar Chart
Advantages of representing data using a Bar Chart are:
- It is used to represent data that is numerical or as categories.
- Since it is a pictorial representation of data, the interpretation of data becomes easy.
- It is time-saving to make comparisons on different categories as data is in pictorial form.
- Decision making regarding various trends becomes easier by viewing the Bar Chart.
Benefits Of Using Histogram
Advantages of representing data using a Histogram are:
- It helps to know and compare the frequency of occurrence of different data ranges.
- Since it is a pictorial representation of the frequency of occurrence of the data ranges, thus the interpretation of data becomes easy.
- Since data range is used, thus large volumes of data can be analyzed.
- Future trends can be predicted much easily by analyzing the large volumes of data that are used in the Histogram.
Drawbacks Of Using Bar Chart
Drawbacks of representing data using a Bar Chart are:
- Since a Bar Chart only displays the values of the categories, any assumptions used or underlying causes cannot be known.
- It might not be feasible where we have too many categories, as each category and its value is to be represented individually on it.
- In order to make any prediction or interpretation, additional information might be needed.
Drawbacks Of Using Histogram
Drawbacks of representing data using a Histogram are:
- It cannot be used for non-consecutive data ranges.
- It cannot be used for overlapping value ranges. In fact, the intervals should be divided in such a way that they are non-overlapping.
- The rectangular blocks cannot be re-ordered as the interval range should be consecutive.
Histogram Vs Bar Graph – Differences
| Bar Chart | Histogram |
|---|---|
| The bars in a Bar Chart represent the value of a particular category. | The rectangles in a Histogram show the frequency of a numerical data range. |
| It is used to compare distinct entities. | It is used to compare the frequencies of data ranges or values that are consecutive and do not overlap. |
| It is generally used to represent data which is categorical e.g. favourite colours, pets etc. | The data represented is generally continuous like height, weight etc. |
| Ordering of the bars drawn can be changed. | Re- ordering of the rectangle blocks cannot be done. |
| Each value to be plotted on a Bar Chart is considered and plotted as a separate entity. | The values to be plotted over a Histogram are divided into consecutive and non-over lapping ranges. |
| The width of bars is generally the same across the Bar Chart. | The width of rectangles created may or may not be the same. |
| There is generally a gap between the bars and they do not touch one another. | The rectangles drawn touch each other and there is no gap between them. |
Frequently Asked Questions
Q #1) What is the difference between a bar graph and a histogram?
Answer: A Bar Chart depicts the values of each data set or category across two axes. For example, in a class of 20 children with varying heights, if we were to draw a Bar Chart, one axis would represent the children and their corresponding height would be marked on the other axis as bars.
Histogram depicts the frequency of a value range across two axes. For example, in a class of 20 children, the count of children for the height range 100-110cm, 111cm-120cm, 121cm-130cm is 6,10 and 4 respectively.
Thus, to draw a Histogram, the count is plotted on one axis and the height range is the other axis and this is represented as rectangular bars that have no gap between them.
Q #2) When should you use a histogram?
Answer: Histogram is preferably used to represent continuous data like age, height, weight, etc. Such data is divided into logical ranges of values that are continuous and non-overlapping. The range is then depicted on one axis and the frequency of their occurrence on the other axis.
Q #3) What does the width of a histogram represent?
Answer: It represents the interval length. A rectangular bar in the Histogram may or may not have equal width.
Q #4) What are bar graphs used for?
Answer: A Bar Graph or a Bar Chart is used to represent the value or count of different categories. The length of a bar represents the value or count of the category over which it is plotted.
Q #5) What is the difference between a bar chart and a column chart?
Answer: A Bar Chart and a Column Chart both are used to represent/compare the value of different categories using bars. However, the only difference between the two is that in a Bar Chart the bars are horizontally aligned, whereas when the bars are vertically aligned, it is known as a Column Chart.
Q #6) What does each bar in a histogram represent?
Answer: Each Bar represents the frequency of occurrence of the data interval over which it is plotted. For example, if the data ranges are 10-20, 21-30, 31-40, then the length of each bar drawn over these ranges would indicate how many times each of the ranges 10-20, 21-30, 31-40 occurs.
Q #7) What can I use instead of the bar graph?
Answer: Sometimes representing data using a Bar Graph might get boring. In such a scenario, there are various alternatives available. Some such examples are the Donut Chart, Pictograms, Stacked Row Chart, Bubble Chart, Radial Column Chart, etc.
Q #8) What are the steps to making a bar graph?
Answer: The below are the steps/points that should be followed:
- Name the Bar Graph, for example, Height of Class II Students
- Decide which axes represent students and which axis represents their height, for example, X-axis for student name and Y-axis for height.
- Label the axes, for example, Student Name for X-axis, Height for Y-axis
- Decide the scale to be used, for example, if the height ranges between 110-140 cm, then one can decide the scale as starting from 110 with an interval of 5.
- Mark and label each point on the axes. So 110, 115, 120, etc. can be plotted on the Y-axis and the student name on X-axis.
- Last, over each student’s name on the x-axis, draw bars with a length equal to the height of that student.
Conclusion
In this article, we covered what is a Bar Chart and Histogram and their areas of use. The benefits of the Bar Chart and Histogram along with the drawbacks.
Also Read =>> Introduction To Graph And Chart Testing
The article also enlisted the difference between histogram and bar graph to give you a quick view of how they differ. Last, we tried answering some of the FAQs related to this topic, which might also be helpful to our readers.