A bar chart or bar graph is a representation of data in the form of rectangular bars where the length fo each bar is proportionate to the value of that they carry. The bar graph can have the bars plotted horizontally or vertically. A vertical bar chart is also called a column bar chart.
The above graph represents the marks attained by student in an Economic class. Here the bar graph represents the absolute values in form of bars. Here the student E has achieved the highest marks in economics, second to him is student H, then C and onwards. Student B has received the lowest marks. In this study the student’s aggregate marks at the term end from 5 different assignments of 20 marks each have been added up to represent the total for the subject in the form of a bar graph.
Pie chart.
A pie chart represents data in a circular chart with the data representing the sectors cut into the pie.
We are here considering an imaginary numbers of people migrating to US in a year for different parts of the world for better future. Here the diagram shows that 51 % of the people migrating to US every year are from the Eastern countries namely japan, Chain, India, Malaysia, etc. 32% of the people come from the Western states or US. Similarly the migration of citizens from the Northern countries or states into US is 14% and from the South is only 3%. Here the whole pie represents the complete count of people migrating which is 100%. Of this 100 % the portions or proportion for East, West, North and South is cut in different colors to represent the protion of the pie they cover with respect to its proportion in 100% .
Histogram
A histogram is a graph which represents frequency distribution. It represents a frequency distribution of a data set by means of bars whose width represents the class interval and whose area is proportional to the corresponding frequencies.
Here in the above diagram we are discussing of a class with 121 students. The above diagram represents the frequency of leaves the students take in an academic year. (Hypothetical figure). Here the graph shows that a count of 10 students are absent in the class for 0 - 10 days in a class. 30 students take 10to 20 days of leave in a year, 26 students take 20 to 30 days of leave. About 32 students are absent or take leave of 30 to 40 days in a year and the maximum number of leaves takes in a year is 40 to 50 days. This is available by a set of 23 students in the class.
