Chapter 8 Residual Analysis Copyright 2012 Pearson Education

Chapter 8 Residual Analysis Copyright © 2012 Pearson Education, Inc. All rights reserved.

Section 8. 1 Introduction Copyright © 2012 Pearson Education, Inc. All rights reserved.

Section 8. 2 Regression Residuals Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 8. 1 Actual random error e and regression residual e^ Copyright © 2012 Pearson Education, Inc. All rights reserved. 4

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Figure 8. 2 SAS printout for firstorder model Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 7

Figure 8. 2 SAS printout for firstorder model (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. 8

Figure 8. 3 SAS printout for quadratic (second-order) model Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 9

Figure 8. 3 SAS printout for quadratic (second-order) model (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. 10

Section 8. 3 Detecting Lack of Fit Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 8. 4 SAS plot of residuals for the first-order model Copyright © 2012 Pearson Education, Inc. All rights reserved. 12

Figure 8. 5 MINITAB plot of cholesterol data with least squares line Copyright © 2012 Pearson Education, Inc. All rights reserved. 13

Figure 8. 6 SAS plot of residuals for the quadratic model Copyright © 2012 Pearson Education, Inc. All rights reserved. 14

Copyright © 2012 Pearson Education, Inc. All rights reserved. 15

Figure 8. 7 SPSS regression printout for demand model Copyright © 2012 Pearson Education, Inc. All rights reserved. 16

Figure 8. 8 SPSS plot of residuals against price for demand model Copyright © 2012 Pearson Education, Inc. All rights reserved. 17

Figure 8. 9 SPSS partial residual plot for price Copyright © 2012 Pearson Education, Inc. All rights reserved. 18

Figure 8. 10 SPSS regression printout for demand model with transformed price Copyright © 2012 Pearson Education, Inc. All rights reserved. 19

Section 8. 4 Detecting Unequal Variances Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 8. 11 A plot of residuals for poisson data Copyright © 2012 Pearson Education, Inc. All rights reserved. 21

Figure 8. 12 A plot of residuals for binomial data (proportions or percentages) Copyright © 2012 Pearson Education, Inc. All rights reserved. 22

Figure 8. 13 A plot of residuals for data subject to multiplicative errors Copyright © 2012 Pearson Education, Inc. All rights reserved. 23

Copyright © 2012 Pearson Education, Inc. All rights reserved. 24

Copyright © 2012 Pearson Education, Inc. All rights reserved. 25

Figure 8. 14 MINITAB regression printout for second-order model of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 26

Figure 8. 15 MINITAB residual plot for second-order model of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 27

Figure 8. 16 MINITAB regression printout for second-order model of natural log of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 28

Figure 8. 17 MINITAB residual plot for second-order model of natural log of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 29

Figure 8. 18 MINITAB regression printout first-order model of natural log of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 30

Figure 8. 19 a SAS regression printout for second-order model of salary: Subsample 1 (years of experience < 20) Copyright © 2012 Pearson Education, Inc. All rights reserved. 31

Figure 8. 19 b SAS regression printout for second-order model of salary: Subsample 2 (years of experience > 20) Copyright © 2012 Pearson Education, Inc. All rights reserved. 32

Section 8. 5 Checking the Normality Assumption Copyright © 2012 Pearson Education, Inc. All rights reserved.

Figure 8. 20 MINITAB histogram of residuals from log model of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 34

Figure 8. 21 MINITAB stem-and-leaf plot of residuals from log model of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 35

Figure 8. 22 MINITAB normal probability plot of residuals from log model of salary Copyright © 2012 Pearson Education, Inc. All rights reserved. 36

Section 8. 6 Detecting Outliners and Identifying Influential Observations Copyright © 2012 Pearson Education, Inc. All rights reserved.

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Figure 8. 23 MINITAB regression printout for model of fast-food sales Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 39

Figure 8. 23 MINITAB regression printout for model of fast-food sales (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. 40

Figure 8. 24 MINITAB plot of residuals versus traffic flow Copyright © 2012 Pearson Education, Inc. All rights reserved. 41

Figure 8. 25 MINITAB plot of residuals versus city Copyright © 2012 Pearson Education, Inc. All rights reserved. 42

Figure 8. 26 MINITAB regression printout for model of fast-food sales with corrected data point Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 43

Figure 8. 26 MINITAB regression printout for model of fast-food sales with corrected data point (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. 44

Figure 8. 27 MINITAB plot of residuals versus traffic flow for model with corrected data point Copyright © 2012 Pearson Education, Inc. All rights reserved. 45

Figure 8. 28 MINITAB plot of residuals versus city for model with corrected data point Copyright © 2012 Pearson Education, Inc. All rights reserved. 46

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Figure 8. 29 SAS regression analysis with influence diagnosis for fast-food sales model Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 48

Figure 8. 29 SAS regression analysis with influence diagnosis for fast-food sales model (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. continued on next slide 49

Figure 8. 29 SAS regression analysis with influence diagnosis for fast-food sales model (cont’d) Copyright © 2012 Pearson Education, Inc. All rights reserved. 50

Section 8. 7 Detecting Residual Correlation: The Durbin. Watson test Copyright © 2012 Pearson Education, Inc. All rights reserved.

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Figure 8. 30 SAS regression printout for model of annual sales Copyright © 2012 Pearson Education, Inc. All rights reserved. 53

Figure 8. 31 SAS plot of residuals for model of annual sales Copyright © 2012 Pearson Education, Inc. All rights reserved. 54

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Figure 8. 32 Rejection region for the Durbin-Watson d-test: scale example Copyright © 2012 Pearson Education, Inc. All rights reserved. 56

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