q08_sol - ISyE2028A, Fall 2010 Solutions to Quiz 8 (version...

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Unformatted text preview: ISyE2028A, Fall 2010 Solutions to Quiz 8 (version A & B) Version A: 1. Which of the following statement is not true if y 3x 7 ? A. The y‐intercept is 7 B. y decreases by 3 when x increases by 4 C. y decreases by 3 when x increases by 1 D. The slope of the line is ‐3 ANSWER: B 2. The simple linear regression model is Y 0 1 x , where is a random variable assumed to be normally distributed with E ( ) 0 and V ( ) 2 . Let x denote a particular value of the independent variable x. Which of the following identities are true regarding the expected or mean value of Y when x x ? A. Y x 0 1 x B. C. E. Y x ( 0 1 ) x Y x 1 x D. Y x 0 Y x 0 ANSWER: A 3. If the error sum of squares is 12 and the total sum of squares is 400, then the proportion of observed y variation explained by the simple linear regression model is A. 0.030 B. 0.173 C. 0.970 D. 0.985 E. None of the above answers are correct. ANSWER: C 4. In simple linear regression analysis, if the residual sum of squares is zero, then the coefficient of determination r 2 must be A. ‐1 B. 0 C. between ‐1 and zero D. 1 E. between ‐1 and 1 ANSWER: D Version B: 5. If the error sum of squares is 6 and the total sum of squares is 400, then the proportion of observed y variation explained by the simple linear regression model is A. 0.030 B. 0.173 C. 0.970 D. 0.985 E. None of the above answers are correct. ISyE2028A, Fall 2010 ANSWER: D 6. In simple linear regression analysis, if the regression sum of squares is zero, then the coefficient of determination r 2 must be A. ‐1 B. 0 C. between ‐1 and zero D. 1 E. between ‐1 and 1 ANSWER: B 7. Which of the following statement is not true if y 3x 7 ? A. The y‐intercept is 7 B. y decreases by 3 when x increases by 1 C. y decreases by 3 when x increases by 4 D. The slope of the line is ‐3 ANSWER: C 8. The simple linear regression model is Y 0 1 x , where is a random variable assumed to be normally distributed with E ( ) 0 and V ( ) 2 . Let x denote a particular value of the independent variable x. Which of the following identities are true regarding the expected or mean value of Y when x x ? Y x 1 x A. Y x 0 B. Y x 0 1 x C. Y x ( 0 1 ) x D. Y x 0 E. ANSWER: C [2 points for submission. 2 points for each question. Total is 10.] ...
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This note was uploaded on 11/16/2010 for the course ISYE 2028 taught by Professor Shim during the Fall '07 term at Georgia Institute of Technology.

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