Statistics Homework Solutions 195

Statistics Homework Solutions 195 - 195 SECTION 8.3 250 (d)...

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Unformatted text preview: 195 SECTION 8.3 250 (d) 200 150 R4 The correlation coefficient between R3 and R4 1 1 is 0.997. 1 100 50 0 0 20 R3 40 60 1 (e) R3 and R4 are nearly collinear. 1 1 (f) The cubic model is best. The quadratic is inappropriate because the residual plot exhibits a pattern. The residual plots for both the cubic and quartic models look good, however, there is no reason to include R 4 in the model 1 since it merely confounds the effect of R3 . 1 Section 8.3 1. (a) False. There are usually several models that are about equally good. (b) True. (c) False. Model selection methods can suggest models that fit the data well. (d) True. 3. (v). x2 , x1 x2 , and x1 x3 all have large P-values and thus may not contribute significantly to the fit. 2 5. (i). Rest, Light*Rest, and Sit*Rest all have large P-values and thus may not contribute significantly to the fit. 7. The four-variable model with the highest value of R2 has a lower R2 than the three-variable model with the highest value of R2 . This is impossible. ...
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This note was uploaded on 12/20/2011 for the course STA 3163 taught by Professor Mattgilg during the Fall '11 term at UNF.

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