Education Technology

How Many Drivers? Investigate the Slope-Intercept Form of a Line

Activity Overview

In this activity, students will be introduced to the slope-intercept form of a linear equation. They will recognize the effects of changes in the slope and y-intercept on the graph of a line. Students will use the Transformation Graphing application to find an approximate linear model of the actual data. They will determine the line of best fit on a scatter plot by using the guess-and-check strategy to manipulate the values of the slope and y-intercept.

Before the Activity

Install the Transformation Graphing application on the students' graphing calculators using one of these two methods:

  • TI-Connect™,  a TI Connectivity Cable, and the Unit-to-Unit Link Cable
  • TI-Navigator™  "send to class" feature
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 1-12 from the attached PDF file for your class
  • During the Activity

    Distribute pages 1-12 to your class.

    Follow the Activity procedures:

  • Plot graphs for the linear equation using the given values of m and b and observe how the graphs change with variations in m and b
  • Write a hypothesis about the effects of m and b on the graph of a line
  • Use the Transformation Graphing application to investigate the effects of varying m and b
  • Notice that the value of m affects the slope of the line and the value of b affects where the line crosses the x-axis
  • Observe the changes in the graph by varying the value of m and b, and compare the results with the hypothesis
  • Prepare a scatter plot showing the relationship between the population and number of licensed drivers in selected states
  • Estimate the value for the slope and y-intercept of a linear model that represents the data
  • Find a line that represents an approximate fit of the data
  • Determine the slope and the y-intercept, and compare with the estimated values
  • Predict the number of licensed drivers for a given population size and verify the prediction
  • After the Activity

    Students will complete the Worksheet and answer questions.

    Review student results:

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