Regression line (1 of 2)
A regression line is a line drawn through a scatterplot
of two variables. The line is chosen so that it comes as close to the points as possible.
The plot shown below is based on the following data:
X Y Y' Y-Y' (Y-Y')²
2 5 4.8 .2 .04
3 6 6.6 -.6 .36
4 9 8.4 .6 .36
5 10 10.2 -.2 .04
four (X,Y) pairs found in the first two columns of the table are indicated
in the plot as the four points. The line in the plot is the best fitting
straight line; it has a slope
of 1.8 and a Y-intercept
of 1.2. Y' represents values along this regression line. The general formula
for Y' is: Y' = bX + A where b is the slope and A is the Y intercept.