Q7. A researcher is interested in the relationship between the number of miles that a used car has been driven (denoted by mileage) and its selling price. Based on a random sample of 60 of a particular model of used cars, the following model was estimated: y=50+31X+ Where 3/ is the selling price (in thousands of E's) and x is the mileage (in thousands of miles). Least-squa res estimates are provided in the table below: Estimate Std. Error (Intercept) 17.49 0 48 mileage 0.17 0 02 You are also told the following: fl n 20': - 502 = 115.7 . 2(5).- 37)2 = 121.8 i=1 i=1 A. Interpret the estimated coefficient on mileage. (2 points) B. Test the null hypothesis that 31:0 against a two-sided alternative using a 5% significance level. (2 points) C. Calculate the coefficient of determination and interpret it in context. (3 points) D. Use the provided information to calculate ?=1(xi 902 (3 points)