Question

in $1,000) of 24 pre-owned pickup . Problem. Andy Williams collected sample data on the mileage (x in 10,000 miles) and the asking price trucks in the Baton Rouge metropolitan area as shown below: Truck Mileage Price ***x==3? V ? (x-99 (y-7) 19 66 12 21 3 6 -199 1,089 121 -11 Total = 1,080 360 1,472 5 75 -165.6 (1) He wants to test if there is a negative relationship between the mileage (x) and the price (Y). Find the p-value for the test. Select one: 00.20 0.10 0.05 0.025 0.01 (2) Suppose that he has developed a simple linear regression model, f = b + b.x. Predict the asking price of a pre-owned pickup truck that ha 45,000 miles on it. Select one: None of the other four $16,500 $16,750 $17,250 $17,525

Answer 1

1)

r=SSxy/sqrt(SSx*SSy) =-165.6/sqrt(1472*575)= -0.18

test statistic t =r*(√(n-2)/(1-r2))

=

-0.858

for n-2=22 degree of freedom and above test statstic , p value =0.200

2)

b1 =SSxy/SSx =-165.6/1472= -0.1125

and bo=(360-1080*(-0.1125))/24 =20.0625

predcited price =20.0625-0.1125*45000 =15 ~ 15000

None of the other four