Here is a YouTube video about Calculating A Linear Regression Using Least Squares Criterion, and is part of a growing collection of videos I have found to be useful. The reason is looking closely at linear regression and what the least square criterion entails and understanding science related to software defined radio.
This tutorial, "Calculating A Linear Regression Using Least Squares Criterion" is free education you can watch, which will help you deepen your knowledge and be better prepared for licence exams, schoolwork, or operating radio equipment.