Fifteen automobiles (197374 models) have three characteristics recorded and described in table. These characteristics include: (mpg) miles/(US) gallon, (disp) engine displacement (cu.in.) and (wt) car weight (1000lbs). (i) List and briefly explain the assumptions of ordinary least squares model with respect to predictor variables, response variables and errors. (ii) Build an ordinary least squares model predicting mpg with the independent variables disp and wt. Are all assumptions of ordinary least squares model met? Please describe why or why not? (iii) Assuming that mpg is the dependent variable, please state the equation of the model, review the significance of the independent variables and the model fit.

	mpg	disp	wt
1	21.4	258	3.215
2	14.3	360	3.57
3	22.8	140.8	3.15
4	19.2	167.6	3.44
5	17.8	167.6	3.44
6	17.3	275.8	3.73
7	15.2	275.8	3.78
8	10.4	472	5.25
9	10.4	460	5.424
10	14.7	440	5.345
11	33.9	71.1	1.835
12	21.5	120.1	2.465
13	27.3	79	1.935
14	26	120.3	2.14
15	15.8	351	3.17