Usually, there is no single line that passes through all the data points, so you try to find the lin

1
Usually, there is no single line that passes
through all the data points, so you try to find
the line that best fits the data. This is called
the best-fitting line.
There are several ways to find the best-fitting
line for a given set of data points. In this
lesson, you will use a graphical approach.
best-fitting line.
2
The winning Olympic discus throws from 1908 to
1996 are plotted in the graph. Approximate the
best-fitting line for these throws.
Write an equation of your line.
3
SOLUTION
Find two points that lie on the best-fitting
line, such as (8, 138) and (96, 230).
Find the slope of the line through these points.
4
y m x b
Write slope intercept form.
Substitute 1.05 for m, 8 for x, 138 for y.
138 (1.05) (8) b
138 8.4 b
y m x b
Simplify.
Solve for b.
129.6 b
5
DETERMINING THE CORRELATION OF X AND Y
In this scatter plot, x and y have a positive
correlation, which means that the points can be
approximated by a line with a positive slope.
6
DETERMINING THE CORRELATION OF X AND Y
In this scatter plot, x and y have a negative
correlation, which means that the points can be
approximated by a line with a negative slope.
7
DETERMINING THE CORRELATION OF X AND Y
In this scatter plot, x and y have relatively no
correlation, which means that the points cannot
be approximated by a line.
8
DETERMINING THE CORRELATION OF X AND Y
Positive Correlation
No Correlation
Negative Correlation