First I am a beginner and am trying to understand linear regression. I was reading an article and saw a formula:
Power = Irradiance * (A + B * Irradiance + C * Temperature + D * Windspeed)
Given the above, the article said that "linear regression is performed on test data to determine constants A, B, C and D". Will someone be able to enlighten me on the constants A to D in a general terms? Will appreciate if someone can point out some website to help me understand linear regression and how to find these constants.