Fitting the curve
With the mouse, drag the data points and their error bars, and see the best fit of the polynomial curve that instantly updates. You can choose the type of fit: linear, quadratic, or cubic. The reduced chi-square statistic shows you when the fit is good. Or you can try to find the best fit manually by adjusting the parameters.
MathTrackX: Polynomials, Functions and Graphs
Linear Algebra I: Linear Equations