Data were collected from a random sample of 220 home sales from a Florida community in 2013. Let Price denote the selling price (in $1,000s), BDR denote the number of bedrooms, Bath denote the number of bathrooms, Hsize denote the size of the house (in square feet), Lsize denote the lot size (in square feet), Age denote the age of the house (in years), and Poor denote a binary variable that is equal to 1 if the condition of the house is reported as "poor." An estimated regression yields P r i c e equals 119.2 plus 0.495 B D R plus 24.4 B a t h plus 0.166 H s i z e plus 0.003 L s i z e plus 0.101 A g e minus 49.8 P o o r comma space top enclose R squared equals 0.72 comma space S E R equals 41.5 space space space space space space space space space space space space left parenthesis 23.9 right parenthesis space left parenthesis 2.51 right parenthesis space space space space space space space space space space left parenthesis 8.94 right parenthesis space space space space space space space left parenthesis 0.011 right parenthesis space space space space space space left parenthesis 0.00048 right parenthesis space space space space space space left parenthesis 0.311 right parenthesis space space space space space space left parenthesis 10.5 right parenthesis space

(a) Is the coefficient of BDR statistically significant at the 5% level? Calculate the relevant t-statistic.

(b) A homeowner purchases 1,500 square feet from an adjacent lot. Construct a 95% confidence interval for the change in the value of her house.

(c) A friend of yours uses the same data to estimate the same regression, but measures Lsize in thousands of square feet. How much would be her estimate of the coefficient of Lsize?

(d) You want to test whether the coefficients of BDR and Age are both equal to zero against the two-sided alternative. (i) How many restrictions are you imposing under the null? (ii) Write down the restricted regression. [To save time, you can just list the regressors in the restricted model.]

(e) Very briefly (in at most 2 sentences) comment on the internal and external validity of the study. [You do not need to be a real estate expert. Just use common sense.]