A corporation has asked you to prepare some multiple regression equations to estimate the effect of variables on fuel economy. The data for this study are shown below, and the dependent variable is miles per gallon Complete parts a and b 19 3
36 5
36 9
Miles
Horsepower
Weight
438
48
1995
328
51
109
39 2
73
2100
19.7
142
3770
204
138
3580
19 1
100
3160
68
60
1885
3360
1890
1990
a Prepare a regression equation that uses vehicle horsepower and vehicle weight as independent variables. Let X, be defined as horsepower and X, be defined as weight
ŷ= 1 + x + x2
(Round to four decimal places as needed)
Interpret the coefficients
For a fixed
V
a 1-unit increase in
V leads to an expected increase of approximately
miles per gallon
b Prepare a second biased regression with vehicle weight not included
(Round to four decimal places as needed)
What can you conclude about the coefficient of horsepower?
In the simple regression model a 1-unit increase in
V leads to a decrease of approximately
miles per gallon​