Suppose you are interested in buying a new Toyota Corolla. Youare standing on the sales lot looking at a model with differentoptions. The list price is on the vehicle. As a salespersonapproaches, you wonder what the dealer invoice price is for thismodel with its options. The following data are based on a randomselection of Toyota Corollas of different models and options. Lety be the dealer invoice (in thousands of dollars) for thegiven vehicle.

x	12.9	13.0	12.8	13.6	13.4	14.2
y	11.6	11.9	11.5	12.2	12.0	12.8

(a) Verify that ?x = 79.9, ?y = 72,?x² = 1065.41, ?y² = 865.1,?xy = 960.02, and r ? 0.980.

?x	=
?y	=
?x2	=
?y2	=
?xy	=
r	=

(b) Use a 1% level of significance to test the claim that? > 0. (Use 2 decimal places.)

t	=
critical t	=

Conclusion

Reject the null hypothesis, there is sufficient evidence that? > 0.

Reject the null hypothesis, there is insufficient evidence that? > 0.    

Fail to reject the null hypothesis, there is insufficientevidence that ? > 0.

Fail to reject the null hypothesis, there is sufficient evidencethat ? > 0.

(c) Verify that S_e ? 0.1039, a ?0.464, and b ? 0.866.

Se	=
a	=
b	=

(d) Find the predicted dealer invoice when the list price isx = 13.6 (thousand dollars). (Use 2 decimal places.)


(e) Find a 90% confidence interval for y when x =13.6 (thousand dollars). (Use 2 decimal places.)

lower limit	=
upper limit	=

(f) Use a 1% level of significance to test the claim that? > 0. (Use 2 decimal places.)

t	=
critical t	=

Conclusion

Reject the null hypothesis, there is sufficient evidence that? > 0.

Reject the null hypothesis, there is insufficient evidence that? > 0.    

Fail to reject the null hypothesis, there is insufficientevidence that ? > 0.

Fail to reject the null hypothesis, there is sufficient evidencethat ? > 0.

(g) Find a 90% confidence interval for ? and interpret itsmeaning. (Use 2 decimal places.)

lower limit	=
upper limit	=

Interpretation

For every $1,000 increase in list price, the dealer priceincreases by an amount that falls within the confidenceinterval.

For every $1,000 increase in list price, the dealer priceincreases by an amount that falls outside the confidenceinterval.    

For every $1,000 increase in list price, the dealer pricedecreases by an amount that falls within the confidenceinterval.

For every $1,000 increase in list price, the dealer pricedecreases by an amount that falls outside the confidenceinterval.