A quadratic function can be drawn as a parabola on a graph. Find out how to plot the graph in this Bitesize KS3 maths video.

Learn and revise how to solve quadratic equations by factorising, completing the square and using the quadratic formula with Bitesize GCSE Maths Edexcel.

But how do you come up with a function to fit data? The basic idea is to create a quadratic function and vary the parameters such that the deviation of the actual data from the function is minimized.

Annie Qu, Bruce G. Lindsay, Bing Li, Improving Generalised Estimating Equations Using Quadratic Inference Functions, Biometrika, Vol. 87, No. 4 (Dec., 2000), pp. 823-836 ...