Fitting a Line to Data
On this web page you will fit lines to data points.
This exploration will help you understand the concepts in Lesson 3.3 of
Discovering Advanced Algebra: An Investigative
This sketch shows ten data points and a line. You can
drag points S and T to change the line. If you
press Fit Data Using Rectangle, you'll see a different line
and a rectangle, both of which are adjustable. You can also drag the
data points or press the Second Data Set button to get a
different data set.
- Drag S and T
until the line is a good fit to the data. Half of the data points
should be on each side of the line.
- For a different approach, press Fit Data Using
Rectangle to show the rectangle. Move the corners of the rectangle
so that it is as small as you can make it while still containing all of
the data points. Now move points P and Q to make
this second line of fit go through the rectangle parallel to the longer
- Press Compare Lines to make the first line
of fit reappear.
- How close are the lines? Which do you think is a
better fit? Explain.
- Press Second Data Set and repeat the
four steps above.
- Which method of finding a line of fit do you prefer?
- How could you find an equation of either line of fit?
- What's an example of a real-life situation in which
you might want a line of fit? Explain.