Using the results in column (1), what is the expected change in price of building a 500-square-foot addition to a house? Construct a 95% confidence interval for the percentage change in price. (Hint: You will need two steps, a unit change of square foot and then multiply it by 500. It is the same for the CI.)

(b) Comparing columns (1) and (2), is it better to use size or ln(size) to explain house prices?

(c) Using column (2), what is the estimated effect of pool on price? (Make sure you get the units right.) Construct a 95% confidence interval for this effect.

(d) The regression in column (3) adds the number of bedrooms to the regression. How large is the estimated effect of an additional bedroom? Is the effect statistically significant? Why do you think the estimated effect is so small? (Hint: which other variables are being held constant?)

(e) Use the regression in column (5) to compute the expected change in price when a pool is added to a house that doesn