Curve Fitting Toolbox

Importing the Data

Before you can import data into the Curve Fitting Tool, the data variables must exist in the MATLAB workspace. For this example, the data is stored in the file census.mat, which is provided with MATLAB.

• load census
  

The workspace now contains two new variables, cdate and pop:

• cdate is a column vector containing the years 1790 to 1990 in 10-year increments.
• pop is a column vector with the US population figures that correspond to the years in cdate.

You can import data into the Curve Fitting Tool with the Data GUI. You open this GUI by clicking the Data button on the Curve Fitting Tool. As shown below, the Data GUI consists of two panes: Data sets and Smooth. The Data Sets pane allows you to

• Import predictor (X) data, response (Y) data, and weights. If you do not import weights, then they are assumed to be 1 for all data points.
• Specify the name of the data set.
• Preview the data.

To load cdate and pop into the Curve Fitting Tool, select the appropriate variable names from the X Data and Y Data lists. The data is then displayed in the Preview window. Click the Create data set button to complete the data import process.

The Smooth pane is described in Importing, Viewing, and Preprocessing Data.

Opening the Curve Fitting Tool

Fitting the Data