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.