12.5 Regression

Making a Scatterplot and Finding the Regression Line

We use GeoGebra's FitLine command to produce a regression line.

Example 1

Make a scatterplot for the points $open parenthesis 10, 12 close parenthesis$ , $open parenthesis 11, 14 close parenthesis$ , $open parenthesis 12, 14 close parenthesis$ , $open parenthesis 12, 16 close parenthesis$ , $open parenthesis 14, 20 close parenthesis$ . Then find the equation of the lease-squares regression line and plot it on top of the scatterplot.

We enter each of the five ordered pairs. The output history will show each labeled with a capital letter, such as $A equals open parenthesis 10, 12 close parenthesis$ .

We do a Zoom to fit: right-click on the Graphics View (or click on the gear icon) and select Zoom to fit.

We next enter the FitLine command:

$fitline ({A, B, C, D, E})$

using the ABC keyboard shown above for the letters, the 123 keyboard (keyboard image) for the parentheses, and the f(x) keyboard (keyboard image) for the list curly braces {}.

Important: We must enter capital letters for the names of the points--GeoGebra is case-sensitive regarding labels.

Modeling, Functions, and Graphs by Katherine Yoshiwara (yoshiwarabooks.org), GNU Free Documentation License 1.2 or later. Adapted for the XYZ HTML edition with the authors' permission (recorded 2026-07-04). License: GFDL-1.2-or-later.