A regression line, also called a "line of best fit," is a straight line drawn through a bunch of data points. The goal when drawing the line is to stay as close to each data point as possible.
Once this line is drawn, you can use it to:
- estimate the general direction or trend in a set of data (e.g., does the data have a positive upward slope or a negative downward slope?)
- determine how one thing moves with another (i.e., the strength of a relationship)
- predict values in the future.