Line graph is also known as line chart. It is one of the most common graphs which is used almost in every field. Line graph is a graph in which points belonging to an observation are plotted on X-Y plane and every two consecutive points are joined together using a straight line. Line graph is named so, because a line is used to represent the data. An example of line graph is given below: Sales of a particular organization in different years.
Line Graphs
Line graph is often used to visualize rate of change of a quantity. It is more useful when the given data has peaks and valleys. Line graphs are very simple to draw and quite convenient to interpret.

The data used in line graph is generally a sample data. Line graph is drawn between two sets of variables one of which is represented on X axis and other on Y axis. One variable is independent variable and usually marked at X axis, while other variable is dependent variable and usually marked at Y axis. The independent variable is generally a qualitative variable in line graph data (Though, It is not mandatory).
Line graph is preferred when rate of change of quantity is observed.
Few examples of the types of data used in line graph are as follows:
  • Speed and time
  • Sales and expenditure
  • Year and production
  • Days and number of an article sold
  • Months and household expenditure
  • States and their population
  • City and temperature
  • Height and weight
  • Age and weight