A residual is positive when it is above the line of fit and negative when it is below it.
Practice makes perfect
A residual is the difference between the y-coordinate of the actual data point and the y-coordinate found using the equation for the line of fit.
y_(actual point) - y_(line of fit)
The residual is positive if the data point lies above the line of fit and is negative if the data point lies below the line of fit.
