Lecture32_HH_PPTX0

# Lecture32_HH_PPTX0 - COMM 291 Applications of Statistics in...

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Click to edit Master subtitle style 5/10/10 Lecture 32/33 Section 201 M/W/F 10:00-11:00 COMM 291 Applications of Statistics in 1 1

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5/10/10 Overview 2 2 A correction on degrees of freedom of DW tests .
5/10/10 The Multiple Regression Model 3 3 For simple regression, the predicted value depends on only one predictor variable : 0 1 ˆ y b b x = + For multiple regression, we write the regression model with more predictor variables : 0 1 1 2 2 ˆ k k y b b x b x b x = + + + + K

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5/10/10 The Multiple Regression Model 4 4 Simple Regression Example: Home Price vs. Bedrooms, Saratoga Springs, NY Random sample of 1057 homes. Can Bedrooms be used to predict Price ? § Approximately linear relationship § Equal Spread Condition is violated. § Be cautious about using inferential methods on these data.
5/10/10 The Multiple Regression Model 5 5 Simple Regression Example: Home Price vs. Bedrooms, Saratoga Springs, NY Computer regression output: The variation in Bedrooms accounts for only 21% of the variation in Price . Perhaps the inclusion of another factor can account for a portion of the remaining variation.

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5/10/10 The Multiple Regression Model 6 6 Multiple Regression: Include Living Area as a predictor in the regression model. Computer regression output: Now the model accounts for 58% of the variation in Price .
5/10/10 The Multiple Regression Model 7 7 Multiple Regression: § Residuals: (as with simple regression) § Degrees of freedom: n = number of observations k = number of predictor variables § Standard deviation of residuals: ˆ e y y = - 1 df n k = - - ( 29 2 ˆ 1 e y y s n k - = - -

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Interpreting Multiple Regression 8 8 NOTE : The meaning of the coefficients in multiple regression can be subtly different than in simple regression. Price drops with increasing bedrooms? Counterintuitive? 28986.10
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## This note was uploaded on 04/29/2010 for the course COMM 291 taught by Professor E.fowler during the Spring '10 term at UBC.

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Lecture32_HH_PPTX0 - COMM 291 Applications of Statistics in...

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