In: Statistics and Probability
Purchasing a car is a difficult decision. Car prices are a function of many variables such as mileage, age, foreign or domestic manufacture and engine technology utilized. Develop and run the following multiple regression model:
What will the expected price of a car be in the lemon market if the age of a car was 8 years, with 9,000 miles on it, is of foreign make and with V6 engine?
Use Car Price ($) | Mileage (Miles) | Age (Years) | Dummy Engine: V6 Technology=0, Not V6 Technology=1 | Dummy Foreign: US=0, Foreign=1 |
26900 | 18000 | 10 | 1 | 1 |
24995 | 18500 | 11 | 0 | 1 |
23998 | 18670 | 12 | 0 | 1 |
22988 | 19000 | 17 | 1 | 0 |
21895 | 19020 | 16 | 0 | 0 |
20995 | 19540 | 18 | 1 | 0 |
19995 | 20001 | 19 | 0 | 0 |
19995 | 20025 | 19 | 0 | 0 |
18995 | 21000 | 18 | 0 | 0 |
18975 | 21250 | 17 | 0 | 0 |
17999 | 22000 | 17 | 0 | 0 |
17995 | 22134 | 18 | 0 | 0 |
17995 | 22345 | 18 | 0 | 0 |
16950 | 23450 | 19 | 1 | 0 |
16922 | 23540 | 20 | 0 | 0 |
16796 | 23780 | 20 | 1 | 0 |
15988 | 24000 | 21 | 0 | 1 |
14995 | 24670 | 22 | 0 | 1 |
14995 | 25000 | 23 | 1 | 1 |
14990 | 25009 | 23 | 1 | 1 |
13877 | 26001 | 24 | 0 | 1 |
11995 | 27001 | 15 | 0 | 1 |
11495 | 27250 | 16 | 0 | 1 |
10990 | 28000 | 17 | 0 | 1 |
The output is:
R² | 0.963 | |||||
Adjusted R² | 0.957 | |||||
R | 0.981 | |||||
Std. Error | 862.818 | |||||
n | 24 | |||||
k | 3 | |||||
Dep. Var. | Use Car Price | |||||
ANOVA table | ||||||
Source | SS | df | MS | F | p-value | |
Regression | 38,74,23,371.9349 | 3 | 12,91,41,123.9783 | 173.47 | 1.75E-14 | |
Residual | 1,48,89,109.6901 | 20 | 7,44,455.4845 | |||
Total | 40,23,12,481.6250 | 23 | ||||
Regression output | confidence interval | |||||
variables | coefficients | std. error | t (df=20) | p-value | 95% lower | 95% upper |
Intercept | 48,683.4807 | |||||
Mileage | -1.2494 | 0.0712 | -17.539 | 1.30E-13 | -1.3979 | -1.1008 |
Age | -148.9609 | 59.7737 | -2.492 | .0216 | -273.6467 | -24.2751 |
Dummy Engine | 499.2701 | 412.3030 | 1.211 | .2400 | -360.7788 | 1,359.3191 |
(a) Use Car Price = 48,683.4807 -1.2494Mileage -148.9609Age + 499.2701Dummy Engine
(b) 96.3%
(c) Yes
(d) Yes
(e) Use Car Price = 48,683.4807 -1.2494Mileage -148.9609Age + 499.2701Dummy Engine Use Car Price = 48,683.4807 -1.2494*45000 -148.9609*10 + 499.2701*0 Use Car Price = $-9029.1283.