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Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 1 1

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 2

Multiple Regression Analysis

Model: 1 1 2 2 ' 'k kY a b X b X b X

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 3

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 4

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 5

Multiple Regression Analysis

Adjusted Coefficient of Determination

2 2 ( 1)1 (1 )

( )

nR R

n k

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 6

Multiple Regression Analysis

Analysis of Variance and F Statistic

/( 1)

/( )

ExplainedVariation kF

UnexplainedVariation n k

2

2

/( 1)

(1 ) /( )

R kF

R n k

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 7

Problems in Regression Analysis

• Multicollinearity: Two or more explanatory variables are highly correlated.

• Heteroskedasticity: Variance of error term is not independent of the Y variable.

• Autocorrelation: Consecutive error terms are correlated.

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 8

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 9

Durbin-Watson Statistic

Test for Autocorrelation

21

2

2

1

( )n

t tt

n

tt

e ed

e

If d = 2, autocorrelation is absent.

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 10

Steps in Demand Estimation

• Model Specification: Identify Variables

• Collect Data

• Specify Functional Form

• Estimate Function

• Test the Results

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 11

Functional Form Specifications

Linear Function:

Power Function:

0 1 2 3 4X X YQ a a P a I a N a P e

1 2( )( )b bX X YQ a P P

Estimation Format:

1 2ln ln ln lnX X YQ a b P b P

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 12

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Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 15

Chapter 4 Appendix

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Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 18

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 19

Getting Started

• Install the Analysis ToolPak add-in from the Excel installation media if it has not already been installed

• Attach the Analysis ToolPak add-in– From the menu, select Tools and then

Add-Ins...– When the Add-Ins dialog appears, select

Analysis ToolPak and then click OK.

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 20

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 21

Entering Data

• Data on each variable must be entered in a separate column

• Label the top of each column with a symbol or brief description to identify the variable

• Multiple regression analysis requires that all data on independent variables be in adjacent columns

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 22

Example Data

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 23

Running the Regression

• Select the Regression tool from the Analysis ToolPak dialog– From the menu, select Tools and then

Data Analysis...– On the Data Analysis dialog, scroll down

the list of Analysis Tools, select Regression, and then click OK

– The Regression tool dialog will then be displayed

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 24

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 25

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 26

Select the Data Ranges

• Type in the data range for the Y variable or select the range on the worksheet

• Type in the data range for the X variable(s) or select the range on the worksheet

• If your ranges include the data labels (recommended) then check the labels option

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 27

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 28

Select an Output Option

• Output to a selected range– Selection is the upper left corner of the

output range

• Output to a new worksheet– Optionally enter a name for the worksheet

• Output to a new workbook

• And then click OK

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 29

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 30

Regression Output

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 31

Multiple Regression Data

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 32

Copyright 2007 by Oxford University Press, Inc.PowerPoint Slides Prepared by Robert F. Brooker, Ph.D. Slide 33

Regression Output

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