Chapter 7 Relationships Among Variables

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Chapter 7 Relationships Among Variables

• What Correlational Research Investigates
• Understanding the Nature of Correlation
• Positive Correlation
• Negative Correlation
• Correlation and Causation
• Pearson Product Moment Correlation
• What the Coefficient of Correlation Means
• Interpreting Reliability of r
• Interpreting Meaningfulness of r

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Regression

• Using Correlation for Prediction
• Working With Regression Equations
• Procedures for Multiple Regression
• Forward-Selection Multiple Regression
• Backward-Selection Multiple Regression
• Maximum R-Squared Method
• Stepwise Regression Procedure
• Multiple Regression Prediction Equations

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Regression Equations

• Y a bX
• b r(s y /s x )
• a M y bM x
• Y a b X b X ... b X Formula for
  straight line
• Calculating beta (slope)
• Calculating intercept (a)
• Standard error of the estimate
• Multiple regression

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Multiple Regression

• What multiple regression does
• Linear combination of Xs Y
• Relationship of each X Y
• Relationship among Xs
• Rs relationship to r
• Test of R F test
• Predictionformula for a straight line
• Y a b 1 X 1 . . . b i X i

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• Approaches to multiple regression
• Forward selection
• Backward selection
• Stepwise selection
• Max R selection
• Shrinkage
• Number of predictors
• Number of subjects
• Cross-validation