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# Emily Smith decides to buy a fuel-efficient used car

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Emily Smith decides to buy a fuel-efficient used car. Here are several vehicles she is considering, with the estimated cost to purchase and the age of the vehicle.

Vehicle Est. Cost Age
Honda insight \$5,555 8
toyota prius \$17,888 3
toyota prius \$9,963 6
toyota echo \$6,793 5
honda civic hybrid \$10,774 5
honda civic hybrid \$16,310 2
chevrolet prizm \$2,475 8
mazda protege \$2,808 10
toyota corolla \$7,073 9
acura integra \$8,978 8
scion xB \$11,213 2
scion xA \$9,463 3
mazda 3 \$15,055 2
mini cooper \$22,705 2

(a) Plot these data on a scatter diagram with estimated cost as the dependent variable.

(b) Find the correlation coefficient.

(c) A regression analysis was performed and the resulting regression equation is Estimated
Cost = 18358 = 1534 Age. Interpret the meaning of the slope.

(d) Estimate the cost of a five-year-old car.

(e) Here is a portion of the regression software output. What does it tell you?

Predictor Coef SE Coef T P
Constant 18358 1817 10.10 0.000
Age -1533.6 306.3 -5.01 0.000

(f) Using the 0.10 significance level, test the significance of the slope. Interpret the result. Is there
a significant between the two variables?

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Plot these data on a scatter diagram with estimated cost as the dependent variable.
The scatter plot is given as follows:

Find the correlation coefficient.
The correlation coefficient is -0.8077.
A regression analysis was performed and the resulting regression equation is Estimated
Cost = 18358 - 1534 Age. Interpret the meaning of the slope.
As the age of the car increases by 1 year, the estimated ...

#### Solution Summary

The solution consists of detailed analysis of the given problem.

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