# College Costs

Author David Graser, Yavapai College, Prescott, AZ (David_Graser@yc.edu)

### Abstract This project originated from an extensive data set of college costs published by the College Board. I needed a first project for my college algebra class that incorporated the concepts surrounding a linear equation and slope. Although this project could be done with almost any type of technology, I required my students to use Excel as well as Mathtype to help them document their work. In this project, each student was given a state for which the average college cost in 2004-2005 and 2007-2008 was known for two year colleges, public four year colleges and private four year colleges. For each type of institution, the student finds the equation of a line through the two data points and predicts when the college costs will double.

• Content Area – College Algebra
• Time Frame – 2 Weeks with Mini Lectures
• Published – April 1, 2008
• Keywords – point-slope form, line, slope, data, linear, rate

### Project Content

Project Letter (DOC | PDF)
Project Data (EXCEL | PDF)

### Scaffolding Resources

Technology Assignment 1 (DOC | PDF) This assignment is designed to get the students graphing their data points on their graphing calculator and in Excel.

How To Graph Two Points on the TI-83 (Video)

How To Graph Two Points in Excel (Video)

Technology Assignment 2 (DOC | PDF) In this assignment, students will solve an equation algebraically and graphically. This should prepare them determining when their college costs have doubled.

Verify the Solution to an Equation Using the TI-83 (Video)

Verify the Solution to an Equation Using Excel (Video)

Show How To Solve an Equation Using Mathtype (Video)

How to Find a Point of Intersection on a TI Graphing Calculator (PDF) This document shows how to put in two equations and find the point of intersection using the intersect command from the CALC menu.

How to Find a Point of Intersection in Excel (PDF) This document shows how to find the point of intersection using GOAL SEEK in Excel.

### Notes

• Some states have institutions whose average costs are decreasing. If you choose to have your students find when costs double, don’t choose one of those states.
• The second worksheet in the Excel file has the annual data for college costs from 2004 to 2008. You could make this into a modeling project or find the equation of a line through a different set of years.
• Students could compare one type of institution in two different states.