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

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.