• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

Algebra 1 : Finding a Line of Best Fit

Published on July 27, 2010

#### Overview

Students make a scatter plot of heart rate versus age data and draw lines of best fit using three different methods - by hand, using the upper and lower quartiles, and using the handheld's regression feature.

#### Key Steps

• Students will create a scatter plot representing resting heart rates versus age.

They graph vertical and horizontal lines to show Q1 and Q3 for both the ages and the heart rates.

• Students set up Lists and labels them AGE and RHR. After entering the information into Lists, they graph a scatter plot.

Students should realize that AGE is the independent variable and RHR is the dependent variable.

• Students find and record the upper and lower quartiles of each data set.

Students then move on to find the intersection of the points, and identify the diagonal across the center rectangle that follows the direction of the points.