"Using the linear models, you can draw a line through data and use that line to explain some of the variation in the data. Now typically the world isn't gonna be perfectly linear. There's going to be lots of extra variation left over, but there's a question of how much of that variation did the line explain. In addition to explaining the variation, the line tells us something about the relationship between our independent variable, x and our dependent variable, y. In particular, we learn the sine on x, like does y increase in x or decrease in x, and we also learn something about the magnitude, so how much does. Each one unit increase of x increased the value of y. So what this linear model can do is help us understand something about data we see in the real world."- Transcript from Scott Page Coursera
Scott Page Model Thinking MOOC Course