1.3. Models and Data http://www.ck12.org
1.3 Models and Data
Learning Objectives
A student will be able to:
- Fit data to linear models.
- Fit data to quadratic models.
- Fit data to trigonometric models.
- Fit data to exponential growth and decay models.
Introduction
In our last lesson we examined functions and learned how to classify and sketch functions. In this lesson we will use
some classic functions to model data. The lesson will be a set of examples of each of the models. For each, we will
make extensive use of the graphing calculator.
Let’s do a quick review of how to model data on the graphing calculator.
Enter Data in Lists
Press[STAT]and then[EDIT]to access the lists,L1 - L6.
View a Scatter Plot
Press2nd [STAT PLOT]and choose accordingly.
Then press[WINDOW]to set the limits of the axes.
Compute the Regression Equation
Press[STAT]then choose[CALC]to access the regression equation menu. Choose the appropriate regression
equation (Linear, Quad, Cubic, Exponential, Sine).
Graph the Regression Equation Over Your Scatter Plot
Go toY=>[MENU]and clear equations. Press[VARS], then enter 5 andEQand press[ENTER](This series of
entries will copy the regression equation to yourY =screen.) Press[GRAPH]to view the regression equation over
your scatter plot
Plotting and Regression in Excel
You can also do regression in an Excel spreadsheet. To start, copy and paste the table of data into Excel. With the
two columns highlighted, including the column headings, click on theCharticon and selectXY scatter. Accept
the defaults until a graph appears. Select the graph, then clickChart, thenAdd Trendline. From the choices of
trendlines chooseLinear.
Now let’s begin our survey of the various modeling situations.
Linear Models