How do you work out the line of best fit?

Question

in a scatter diagram do you work out the line of best fit or is it just a guess?

Answer 1

Computers use complicated formulas when using Excel or similar programs, but for drawn graph you have to estimate.

Just make sure that:

-there are roughly the same amount of points above and below the line.

-the line is what it's meant to be (for example if it's a linear relationship make sure you've drawn a straight line).

-the line goes through the origin if it's meant to (this is not always the case).

-the points are as close to the line as possible.  

Answer 2

No, you definitely do not guess. You draw the line of best fit with the dots that looks to you are on a straight line.