The line of best fit does not have to start from 0.
Yes but phrased differently
The line that minimized the sum of the squares of the diffences of each point from the line is the line of best fit.
A line of best-fit.
Because the "best fit" line is usually required to be a straight line, but the data points are not all on one straight line. (If they were, then the best-fit line would be a real no-brainer.)
The line of best fit is the best possible answer you can get from raw data. They also can be used to make predictions.
Finding the line of best fit is called linear regression.
A best-fit line is the straight line which most accurately represents a set of data/points. It is defined as the line that is the smallest average distance from the data/points. Refer to the related links for an illustration of a best fit line.
A straight line equation
Check out the related links section below to see an example of a line of best fit.