Bar Charts (DI)

What is a Bar Chart in Data interpretation?

Bar chart is graphical representation of data wherein vertical bars are placed equidistant from each other. It consists of rectangular bars with variable heights. The height of each bar represents the value of the quantity it represents. Bar graphs are ideal for comparing numbers and data. Bar graphs have vertical and horizontal axes known as the x and y-axis, respectively.

Properties of Bar Graphs? 

  • Data is represented as a number of Vertical or Horizontal bars.
  • Value of parameter is (generally) proportional to the length of the bar. 
  • Hence, it is represents a set of discrete points.
  • Simpler and more accurate to interpret as compared to Line Graphs since interpolation or extrapolation of values is not required
  • The bars are rectangular with an equal width 
  • All the bars are at an equal distance from each other.
  • The bars can be drawn vertically or horizontally.
  • The bars are plotted on a common base.
  • Their height represents the value of the quantity represented by the graph.

Type of Bar charts:

  • Simple bar chart
  • Stacked bar chart: Each bar is further divided into segments
  • Clustered bar charts: Here a cluster of two or more bars are given for each value of parameter.
  • 100% stacked bar: Similar to stacked bar chart except that length of each bar is segmented on percentage basis.

Example :  

The bar graph given below shows the foreign exchange reserves of a country (in million US $) from 1991 - 1992 to 1998 - 1999.

Foreign Exchange Reserves Of a Country. (in million US $)

 

Questions: 

The ratio of the number of years, in which the foreign exchange reserves are above the average reserves, to those in which the reserves are below the average reserves is?

Solution

Average foreign exchange reserves over the given period = 3480 million US $.

The country had reserves above 3480 million US $ during the years 1992-93, 1996-97 and 1997-98, i.e., for 3 years and below 3480 million US $ during the years 1991-92, 1993-94, 1994-95, 1995-56 and 1998-99 i.e., for 5 years.

Hence, required ratio = 3 : 5.

Questions :

The foreign exchange reserves in 1997-98 was how many times that in 1994-95? 

Solution

Required ratio = 5040 = 1.5.
3360