Bar Graph

A bar graph is a pictorial rendition of statistical data in which the  independent variable can attain only certain discrete values. The dependent variable may be discrete or continuous. The most common form of bar graph is the vertical bar graph, also called a column graph.

In a vertical bar graph, values of the independent variable are plotted along a horizontal axis from left to right. Function values are shown as shaded or colored vertical bars of equal thickness extending upward from the horizontal axis to various heights. In a horizontal bar graph, the independent variable is plotted along a vertical axis from the bottom up. Values of the function are shown as shaded or colored horizontal bars of equal thickness extending toward the right, with their left ends vertically aligned.

Bar Graphs are most commonly used for data interpretation as they can be easily analysed vertical (or) Horizontal bars are given to interpret the data to deduce the required information.

Ex. Study the following bar graph carefully and answer the questions given below Imports and exports of a country from 2000 - 2001 to 2004 -2005

1.In which of the following year the gap between the import and export was maximum.
1. 2001-2002  
2. 2002-2003  
3. 2003-2004  
4. 2004-2005

2.In which of the following year the gap between the imports and exports was minimum
1. 2002 - 2003  
2. 2003 - 2004  
3. 2004 - 2005  
4. None of these

3. The exports in 2001 - 2002 was approximately how many times that of the year 2003- 2004.
1. 2    
2. 3    
3. 4    
4. 5

4. Give the ratio between the number of years in which export is greater than imports and import is greater than exports.
1. 3 : 2    
2. 2 : 3    
3. 3 : 1    
4. 1 : 3

5. Give the difference between the average of imports and exports
1. 100  
2. 90  
3. 80  
4. 70

Solutions

1. It is very clear from the graph that the gap between import and export was maximum
    in 2003-2004
    Therefore, Correct option is '3'

2. From the graph we can say that the gap between imports and exports
    is minimum in 2004-2005
    i.e. 400 - 350 = 50 core
    Therefore, Correct option is '3'

3. The exports of the year 2001 - 2002 = 600
    The exports of the year 2003 - 2004 = 150
    Therefore, Exports of 2001 - 2002 is 4 times greater than the exports of 2003 -
     2004
    Therefore, Correct option is '3'

4. In 2 years i.e. 2000 - 2001 and 2001 -2002 exports are greater than imports In 3
    years i.e. 2002 - 2003, 2003 - 2004 and 2004 - 2005 imports are greater than
    exports.
    Therefore, Correct option is '2'

5. Average of imports in the span of 2000 - 2005
   Average of exports in the span of 2000 - 2005
   Therefore, Difference = 470 - 400 = 70
   Therefore, Correct option is '4'

Exercise Questions

Directions  for  Questions  1  to  4:  Answer  the  questions  on  the  basis  of   the information  given  below.  Purana  and  Naya  are two  brands  of  kitchen   mixer- grinders available in the local market. Purana is an old brand that was introduced in 1990, while Naya was introduced in 1997. For both these brands, 20% of the mixer- grinders bought in a particular year are disposed off as junk exactly two years later. It is known that 10 Purana mixer -grinders were disposed off in 1997. The following figures show  the number  of Purana and Naya  mixer- grinders  in operation  from 1995 to 2000, as at the end of the year.

1. How many Naya mixer -grinders were purchased in 1999?

a. 44         
b. 50            
c. 55                
d. 64

2. How many Naya mixer -grinders were disposed off by the end of2000?

a. 10          
b. 16    
c. 22    
d. Cannot be determined from the data

3. How many Purana mixer-grinders were purchased in 1999?

a. 20    
b. 23    
c. 50    
d. Cannot be determined from the data

4. How many Purana mixer-grinders were disposed off in 2000?

a. 0     
b. 5      
c. 6      
d. Cannot be determined from the data

The table above shows imports for three types of steel over a six month period. Use this information to answer the following questions.

5. Which month showed the largest decrease in total imports over the previous month?

a. Feb            
b. Mar                 
c. April           
d. May         

6. What was the total value of sheet steel (in $) imported over the 6 month period?

a. 56,750        
b.75,300         
c. 55,550        
d. 42,370        

7. What was the percentage of scrap steel imported in the 6 month period?

a. 37.5           
b. 35.2             
c. 36.1            
d. 31.2        

8. What was the difference (in thousands of tons) between coil steel and sheet steel
imports in the first 3 months of the year?

a. 10               
b.16                
c. 18               
d. 20

9. What was the approximate ratio of sheet steel and coil steel imports in the first 3
    months of the year?

a. 11:9    
b. 8:9        
c. 7:11            
d. 3:8     

Answer Key

1.b; 2.b; 3.a; 4. d; 5.b; 6.c; 7.d; 8.d; 9.a