Chapter 7 Some Regression Pitfalls

Section 7.1 Introduction

Section 7.2 Observational Data versus Designed Experiments

Section 7.3 Parameter Estimability and Interpretation

Figure 7.1 Creativity and flexibility data for three children Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.2 Only two different x-values observed - the second-order model is not estimable Copyright © 2012 Pearson Education, Inc. All rights reserved.

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.3 SAS output for interaction model, Example 7.3 Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.4 SPSS regression printout for grandfather clock model Copyright © 2012 Pearson Education, Inc. All rights reserved.

Section 7.4 Multi-collinearity

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.5 SAS regression printout for FTC model Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.6 SAS correlation matrix for independent variables in FTC model Copyright © 2012 Pearson Education, Inc. All rights reserved.

Section 7.5 Extrapolation: Predicting Outside the Experimental Region

Figure 7.7 Using a regression model outside the experimental region Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.8 Experimental region for modeling GDP (y) as a function of inflation rate (x1) and prime interest rate (x2) Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.9 MINITAB descriptive statistics for independent variables, Example 7.6 Copyright © 2012 Pearson Education, Inc. All rights reserved.

Section 7.6 Variable Transformations

Figure 7.10 Hypothetical relation between demand y and price p Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.11a,b,c&d Graphs of some mathematical functions relating E(y) to p Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.11e,f&g Graphs of some mathematical functions relating E(y) to p Copyright © 2012 Pearson Education, Inc. All rights reserved.

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.12 MINITAB regression printout for Example 7.8 Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 7.13 Graph of the demand - price curve for Example 7.8 Copyright © 2012 Pearson Education, Inc. All rights reserved.