Generally, in two mutually related statistical series, the regression analysis based on graphic method. Under graphic method the values of X and Y variable are plotted on a graph paper in the form of a scatter Diagram .When two lines are drawn passing nearest to the dots, these are known as regression line. If these lines are straight, the regression is called as linear. The equations of these straight regression lines are called equations of the first degree. Regression equation of y on x : y =a+bX and regression equation of X and y:x =a+by. If these regression lines take the form of smooth curve, the regression will be called as curvilinear.