Theory:

Statistics is a branch of mathematics that deals with the collection, organization, presentation and analysis of data. Statistical data has great use in different fields such as research, medicine, education, economy, business and weather.
 
In previous classes, you have seen how to collect information, arranging it in frequency distribution table and put that information as a visual representation in the form of pictogram, table or bar graphs.
 
Why we need a bar graph to represent data? Sometimes, when a large number of data is organized in tabular form, it is difficult to draw meaningful conclusions from it. But, if the same data is represented pictorially or graphically, it becomes easier to understand and analyse it. Here, we discuss the bar graph and its types.
Bar Graph: A bar graph is a pictorial representation of data. A bar graph consists of equally - spaced parallel bars (Horizontal or Vertical) whose lengths/heights will vary according to the number of items given.
    Important!
  • The lengths of the bar depend upon the frequency and the scale chosen.
  • The width of each bar is the same.
  • The space between any two bars is also the same.
We can use bar graphs to show the relative sizes of many things, such as what flavour of ice-cream people have, how many customers a shop has on different days and so on.
Example:
Consider the following bar graph.
 
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This bar graph shows the relative number of favourite icecreams among the different flavours. It can be directly concluded from the graph that 'Group of people feels that Chocolate flavour is the favourite ice-cream'.