I'm trying to come up with an equation for the AP grading scale. My first attempt was to just use a simple quadratic equation, and get it as close as possible to the curve, then I came up with the idea to use a polynomial regression, however, it doesn't hit each of my points exactly (tis the nature of a regression) Is there some kind of curve that hits each data point rather than roughly estimating the closest curve?
This is what I have so far:
The black dots are my data points (I added a few extra to make the regression turn the way I want it to), The orange curve is my attempt at quadratic, and the green equation is the regression. https://www.desmos.com/calculator/mg75cjdr80