What are some real life applications of least squares problem?

Question

I'm looking for some applications that require solving the least square problem. I know polynomial fitting is one of them, but sure there are many others.

Thanks

Answer 1

Carl Gauss used this method to approximate the orbit of Ceres from the few observations that had been made of it, after which it was lost in the glare of the sun. Gauss predicted where it would be, and the astronomers looked where he said, and there it was.

Answer 2

The applications are vast and numerous, but one very useful one I have personal experience with is fitting financial models to real world data. This helps traders decide how best to distribute assets in order to achieve whatever goal they've set out to achieve, and with some ups and downs they eventually end up making a lot of money.