# Bar Graph

Sub Topics

Bar graph is a pictorial representation or the visual representation of different frequencies of large date handling that can be put in terms of bars which makes the concept  to  grasp easily and come to conclusion or prediction of certain application that is going to make a profit or minimize a profit. For example, while presenting the population for the last five decades, one can only depict the total population in the bar charts, and not its gender wise distribution.

## Bar Graph Definition

A bar chart or a Bar Graphs is a graphical representation of frequencies in the form of horizontal or vertical bars of equal width for a given frequency distribution.

## Bar Graph Examples

Consider the example of plotting a Bar Graphs for the frequency distribution of blood groups in a blood donation camp.

• To construct a bar graph we first draw a horizontal line and place tick marks at equal intervals along the line. Each tick mark represents a possible value of the variable. In our example these marks will be O, A, B, AB respectively.

• We then draw vertical bars that represent the frequency. Each bar is of equal width and height is proportional to the frequency of that value.

Conventionally, the bars do not touch each other giving a feel that the data set is discrete and not continuous.

Construct a simple bar chart for the following frequency distribution.

 Class (Blood Group) Frequency O 4 A 7 B 5 AB 4 Total 20

## Multiple Bar Graph

We can also draw multiple bars for comparing two or more sets of statistical data. Bars are constructed side by side to represent the set of values for comparison. In order to distinguish, the bars must be unique and index be prepared for each type.

## Bar Graph Chart

For Graph theory, Construct a bar graph for the given frequency distribution.

 Year profit before tax(million dollars) profit after tax (million dollars) 2005 120 52 2006 150 95 2007 185 100 2008 165 80 2009 200 107

We will construct a vertical bar chart here based on the same principles (equidistant, equal width etc.)

As one can see both bars are distinguished by different colours and an index is also maintained.

## Creating a Bar Graphs

Represent the following data (production of fish) by a sub-divided bar diagram

 Year Marine(million tonnes) Inland(million tonnes) Total(million tonnes) 2006 4.75 3.29 8.04 2007 5.99 4.35 10.34 2008 8.25 6.11 14.36 2009 12.45 9.41 21.86 2010 14.66 11.01 25.67