The graph of the quadratic function y = a x 2 + b x + c has a minimum turning point when a> 0 and a maximum turning point when a a <0. The turning point lies on the line of symmetry.

Revise how to recognise and determine the equation of a quadratic function from its graph. BBC Bitesize Scotland revision for SQA National 5 Maths.

Second, it gives you uncertainties in the coefficients of the fitting function. Plot 0.997: I call it Plot 0.997 because if you just do a google search for Plot you will never find it.