Geogebra – Regression Analysis
http://www.geogebra.org/cms/en/
LINEAR REGRESSION
Example 1: Plot the following data and find the equation of the
line of best fit.
X
62
116
55
30
46
Steps:
1. Open the Perspectives Panel (if not already open). On the right, click on the
triangle, to open the ‘Perspectives’ panel (Figures 1 and 2)
Figure 1 Figure 2
2. Select Spreadsheet & Graphics
3. Enter the data (Figure 3)
Figure 3
Y
225
360
215
150
180
4. Highlight all the data – click on the red triangle in the bottom corner of the 2nd item
(see Figure 4) – select Two Variable Regression Analysis (Figure 5)
Figure 4 Figure 5
5. Another window will pop open – click Analyze
(Figure 6)
Figure 6
6. After you click Analyze, the window
will display the ScatterPlot (Figure 7).
Figure 7
7. In the bottom left corner, you
can select the Regression Model
you want – select Linear. (Figure 8)
Figure 8
NOTE: with Geogebra, you can:
 Copy to graphics view
 Copy to clipboard (and then paste into a word processing document)
 Export as picture
POLYNOMIAL REGRESSION
Example 2: Plot the following data and find the equation of the
line of best fit.
Steps:
1. Start Geogebra (or open a new window if
already open)
2. Open the Perspectives Panel (if not already
open). Select Spreadsheet & Graphics.
3. Enter the data
4. Highlight the data
5. Using the 2nd button (below the menu),
choose Two Variable Regression Analysis (you
may need to click on the red triangle in the
corner) (Figure 9)
6. Click Analyze
Figure 9
7. When you click analyze, your window
will show the plotted points
8. From the drop down list in the bottom
left corner, select the Regression Model
you want (Polynomial for quadratic or
cubic, Linear for linear)
Question: Is the line of best fit linear,
quadratic or cubic?
Answer: the data appears to be
quadratic
Select Polynomial – the default setting for
the degree of the polynomial is ‘2’
(quadratic) – see figure 10 – notice how
the line of best fit is a good match for the
data
Figure 10
X
0
1
2
3
4
5
6
7
8
Y
0
350
600
750
800
780
600
350
0
POLYNOMIAL REGRESSION (con’t)
Example 3: Plot the following data and find the equation of the
line of best fit.
Steps:
1. Start Geogebra (or open a new window if already open)
2. Open the Perspectives Panel (if not already open). Select
Spreadsheet & Graphics.
3. Enter the data
4. Highlight the data
5. Using the 2nd button (below the menu), choose Two
Variable Regression Analysis (you may need to click on the red
triangle in the corner) (Figure 9)
6. Click Analyze
7. When you click analyze, your window will show the plotted points
8. From the drop down list in the
bottom left corner, select the Regression
Model you want (Polynomial for
quadratic or cubic, Linear for linear)
Question: Is the line of best fit linear,
quadratic or cubic?
Answer: the data appears to be cubic
Select Polynomial –set the degree of the
polynomial to ‘3’ for a cubic regression
– see figure 11 – notice how the line of
best fit is a good match for the data
Figure 11
X
0
1
2
3
4
7
8
9
12
14
17
20
22
23
24
25
26
27
28
29
Y
21.98
26.18
35.63
43.26
45.92
45.78
49.75
47.53
57.05
54.18
58.52
59.43
70.56
70
74.48
82.32
92.82
97.86
102.27
115.29