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Exploring the Goodness of Fit in Linear Models - The SCATTER Spreadsheet

Scott A. Sinex

I use the interactive spreadsheet scatter.xls to have students discover some basic characteristics of scatter in data and how they influence the goodness of fit.  The spreadsheet includes four separate worksheets to explore scatter, outliers, and curvature. My mode of questioning with students is embedded in the following discussion as the worksheets are introduced. The individual worksheets are keyed to the tabs at the bottom of the Excel screen as shown in Figure 5. 

Figure 5. Tabbed worksheets within the scatter.xls spreadsheet

The spreadsheet also includes introduction of residuals, since the value of r2 fails to take into account the effect of minor curvature in data.  I have placed Comment boxes within the worksheets to explain the various operations. These comment boxes are denoted by a little red triangle in upper right corner of a cell; if you place the cursor on the cell, the comments appear.

I also provide a sample student activity.

Scott A. Sinex, "Exploring the Goodness of Fit in Linear Models - The SCATTER Spreadsheet," Convergence (March 2005)