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CHAPTER 13 Simple Linear Regression

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554 <strong>CHAPTER</strong> THIRTEEN <strong>Simple</strong> <strong>Linear</strong> <strong>Regression</strong><br />

SUMMARY<br />

As you can see from the chapter roadmap in Figure <strong>13</strong>.24,<br />

this chapter develops the simple linear regression model<br />

and discusses the assumptions and how to evaluate them.<br />

Once you are assured that the model is appropriate, you can<br />

predict values by using the prediction line and test for the<br />

significance of the slope.<br />

<strong>Simple</strong> <strong>Linear</strong> <strong>Regression</strong><br />

and Correlation<br />

<strong>Regression</strong><br />

Least-Squares<br />

<strong>Regression</strong> Analysis<br />

Scatter Plot<br />

Primary<br />

Focus<br />

Correlation<br />

Coefficient<br />

of Correlation, r<br />

Testing H 0 :<br />

ρ = 0<br />

Prediction Line<br />

Plot Residuals<br />

over Time<br />

Compute<br />

Durbin-Watson<br />

Statistic<br />

Yes<br />

Data<br />

Collected<br />

in Sequential<br />

Order<br />

?<br />

No<br />

Residual Analysis<br />

Use Alternative to<br />

Least-Squares <strong>Regression</strong><br />

Yes<br />

Is<br />

Autocorrelation<br />

Present<br />

?<br />

No<br />

Yes<br />

Model<br />

Appropriate<br />

?<br />

No<br />

Testing H 0 :<br />

β 1 = 0<br />

(See Assumptions)<br />

No<br />

Model<br />

Significant<br />

?<br />

Yes<br />

Use Model for<br />

Prediction and Estimation<br />

Estimate<br />

β 1<br />

Estimate<br />

µ YlX=X i<br />

Predict<br />

Y X=X i<br />

FIGURE <strong>13</strong>.24 Roadmap for simple linear regression

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