A graph is a pictorial representation of numerical data. Generally, the data used in statistics or other fields is vast and it is difficult to read all the data items and interpret the results. Graphical representation is very helpful in making comparisons, interpreting various results and even forecasting many possibilities. A graph is diagram which shows relationship between two variables. These variables are usually defined on X and Y axis. One variable is independent and is generally represented on X-axis, while the other variable is dependent and is generally represented on Y-axis.

Graph and chart are ambiguous words. They make a difficult data easy to understand. One can interpret the results by just having a look at graph or chart. There are different types of graphs and charts. Few of them are listed below:
  • Line graph
  • Pie chart
  • Bar graph or bar diagram
  • Scatter plot or scatter graph
  • Stem and leaf plot or stem plot
  • Histogram
  • Frequency polygon
  • Frequency curve
  • Cumulative frequency curve.