Activities

• • • Subject Area

• Math: Algebra I: Exponential Functions
• Math: Statistics: Inferential Statistics

• Author 9-12

60 Minutes

• Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• Other Materials
This is Activity 7 from the EXPLORATIONS Book:
Activities for Algebra with the TI-83 Plus.

The following materials are required for this activity:
• Metric ruler (meter stick)
• String of length: 1.5 meters
• Eye test sheets with letters

Now You See It, Now You Don't - TI-83

Activity Overview

In this activity, students study the relationship between age and near point accommodation (NPA). They predict a person's age using NPA distance values. They use exponential regression, create box-and-whisker plots and histograms.

Before the Activity

• Set up the calculator for data collection using the procedure described in the attached Appendix PDF file
• See the attached PDF file for detailed instructions for this activity
• Print pages 87 - 96 from the attached PDF file for your class
• During the Activity

Distribute the pages to your class.

• Measure the closest distance between the eye and the paper when the letter on the paper remains in focus (NPA)
• Record the age, and the distance between the eye and the paper
• Repeat the procedure with 4 different subjects
• Enter the age and NPA data as lists
• Group the data for different age groups
• Create a box-and-whisker plot to analyze the data
• Use the graph of the exponential regression to determine the person's age based on his NPA distance
• After the Activity

Students will complete the Data Collection and Analysis page and answer questions listed on it.

Review student results:

• As a class, discuss questions that appeared to be more challenging
• Re-teach concepts as necessary