investigation 10

# Investigation 10 - Investigation 10 Used Car Prices Michelle Robertson Section 2 Megan Marques Section 1 December 1 2006 Stat 221 a The least

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Michelle Robertson Section 2 Investigation 10 - Used Car Prices Megan Marques Section 1 December 1, 2006 Stat 221 a. The least squares line is price (k) = 18785-1397(age) age Price 14 12 10 8 6 4 2 0 25000 20000 15000 10000 5000 0 S 2295.21 R-Sq 67.3% R-Sq(adj) 66.9% Fitted Line Plot Price =  18785 - 1397 age b. The proportion of variability is .673. c. Ho: ß ≠ 0 ( no relation ) Ha: ß = 0 ( relationship ) T= b T = 1397 = 13.446 Degrees of Freedom = 90-2=88 P-value = 0.00 SEb 103.9 We have very strong evidence against the null hypothesis (Ho). There is strong evidence that ß is = 0 meaning that there is a relationship. This means that there is a relationship between the price and the age of the car. Older cars will cost less and newer cars will cost more. d. b +/- t*(SEb) = 1397 +/- (2.00)(103.9) = (1604.8 – 1189.2) This parameter and interval mean that for each additional year old the car is the price of the car decreases by between \$1604.8 and \$1189.2. e.

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## This note was uploaded on 04/14/2008 for the course STAT 221 taught by Professor Lund during the Spring '05 term at Cal Poly.

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Investigation 10 - Investigation 10 Used Car Prices Michelle Robertson Section 2 Megan Marques Section 1 December 1 2006 Stat 221 a The least

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